Thioether substituted imidazoquinolines

ABSTRACT

Imidazoquinoline and tetrahydroimidazoquinoline compounds that contain thioether functionality at the 1-position are useful as immune response modifiers. The compounds and compositions of the invention can induce the biosynthesis of various cytokines and are useful in the treatment of a variety of conditions including viral diseases and neoplastic diseases.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.10/696,684, filed Oct. 29, 2003, now U.S. Pat. No. 6,921,826, which is acontinuation of U.S. application Ser. No. 10/013,059, filed Dec. 6,2001, now U.S. Pat. No. 6,664,264, which claims the benefit of U.S.Provisional Application No. 60/254,218, filed Dec. 8, 2000.

FIELD OF THE INVENTION

This invention relates to imidazoquinoline compounds that have thioetherfunctionality at the 1-position, and to pharmaceutical compositionscontaining such compounds. A further aspect of this invention relates tothe use of these compounds as immunomodulators, for inducing cytokinebiosynthesis in animals, and in the treatment of diseases, includingviral and neoplastic diseases.

BACKGROUND OF THE INVENTION

The first reliable report on the 1H-imidazo[4,5-c]quinoline ring system,Backman et al., J. Org. Chem. 15, 1278–1284 (1950) describes thesynthesis of1-(6-methoxy-8-quinolinyl)-2-methyl-1H-imidazo[4,5-c]quinoline forpossible use as an antimalarial agent. Subsequently, syntheses ofvarious substituted 1H-imidazo[4,5-c]quinolines were reported. Forexample, Jain et al., J. Med. Chem. 11, pp. 87–92 (1968), synthesizedthe compound 1-[2-(4-piperidyl)ethyl]-1H-imidazo[4,5-c]quinoline as apossible anticonvulsant and cardiovascular agent. Also, Baranov et al.,Chem. Abs. 85, 94362 (1976), have reported several2-oxoimidazo[4,5-c]quinolines, and Berenyi et al., J. Heterocyclic Chem.18, 1537–1540 (1981), have reported certain2-oxoimidazo[4,5-c]quinolines.

Certain 1H-imidazo[4,5-c]quinolin-4-amines and 1- and 2-substitutedderivatives thereof were later found to be useful as antiviral agents,bronchodilators and immunomodulators. These are described in, interalia, U.S. Pat. Nos. 4,689,338; 4,698,348; 4,929,624; 5,037,986;5,268,376; 5,346,905; and 5,389,640, all of which are incorporatedherein by reference.

There continues to be interest in the imidazoquinoline ring system.

Certain 1H-imidazo[4,5-c]naphthyridine-4-amines, 1H-imidazo[4,5-c]pyridin-4-amines, and 1H-imidazo[4,5-c]quinolin-4-amines havingan ether containing substituent at the 1 position are known. These aredescribed in U.S. Pat. Nos. 5,268,376; 5,389,640; 5,494,916; and WO99/29693.

Despite these attempts to identify compounds that are useful as immuneresponse modifiers, there is a continuing need for compounds that havethe ability to modulate the immune response, by induction of cytokinebiosynthesis or other mechanisms.

SUMMARY OF THE INVENTION

We have found a new class of compounds that are useful in inducingcytokine biosynthesis in animals. Accordingly, this invention providesimidazoquinoline-4-amine and tetrahydroimidazoquinoline-4-aminecompounds that have a thioether containing substituent at the1-position. The compounds are defined by Formulas (I) and (II), whichare defined in more detail infra. These compounds share the generalstructural formula:

wherein X, Z, R₁, R₂, and R are as defined herein for each class ofcompounds having formulas (I) and (II).

The compounds of formulas (I) and (II) are useful as immune responsemodifiers due to their ability to induce cytokine biosynthesis andotherwise modulate the immune response when administered to animals.This makes the compounds useful in the treatment of a variety ofconditions such as viral diseases and tumors that are responsive to suchchanges in the immune response.

The invention further provides pharmaceutical compositions containingthe immune response modifying compounds, and methods of inducingcytokine biosynthesis in an animal, treating a viral infection in ananimal, and/or treating a neoplastic disease in an animal byadministering a compound of Formula (I) or (II) to the animal.

In addition, the invention provides methods of synthesizing thecompounds of the invention.

DETAILED DESCRIPTION OF THE INVENTION

As mentioned earlier, we have found certain compounds that inducecytokine biosynthesis and modify the immune response in animals. Suchcompounds are represented by Formulas (I) and (II) as shown below.

Imidazoquinoline compounds of the invention, which have thioetherfunctionality at the 1-position are represented by Formula (I):

wherein: X is —CHR₃—, —CHR₃-alkyl-, or —CHR₃-alkenyl-;

-   -   Z is —S—, —SO—, or —SO₂—;    -   R₁ is selected from the group consisting of:        -   -alkyl;        -   -aryl;        -   -heteroaryl;        -   -heterocyclyl;        -   -alkenyl;        -   —R₄-aryl;        -   —R₄-heteroaryl;        -   —R₄-heterocyclyl;    -   R₂ is selected from the group consisting of:        -   -hydrogen;        -   -alkyl;        -   -alkenyl;        -   -aryl;        -   -heteroaryl;        -   -heterocyclyl;        -   -alkyl-Y-alkyl;        -   -alkyl-Y-alkenyl;        -   -alkyl-Y-aryl; and        -   -alkyl or alkenyl substituted by one or more substituents            selected from the group consisting of:            -   —OH;            -   -halogen;            -   —N(R₃)₂;            -   —CO—N(R₃)₂;            -   —CO—C₁₋₁₀ alkyl;            -   —CO—O—C₁₋₁₀ alkyl;            -   —N₃;            -   -aryl;            -   -heteroaryl;            -   -heterocyclyl;            -   —CO-aryl; and            -   —CO-heteroaryl;    -   each R₃ is independently H or C₁₋₁₀ alkyl;    -   each R₄ is independently alkyl or alkenyl;    -   each Y is independently or —O— or —S(O)₀₋₂—;    -   n is 0 to 4; and    -   each R present is independently selected from the group        consisting of C₁₋₁₀ alkyl, C₁₋₁₀ alkoxy, hydroxy, halogen and        trifluoromethyl;        or a pharmaceutically acceptable salt thereof.

The invention also includes tetrahydroimidazoquinoline compounds thatbear a thioether containing substituent at the 1-position. Suchtetrahydroimidazoquinoline compounds are represented by Formula (II):

wherein: X is —CHR₃—, —CHR₃-alkyl-, or —CHR₃-alkenyl-;

-   -   Z is —S—, —SO—, or —SO₂—;    -   R₁ is selected from the group consisting of:        -   -alkyl;        -   -aryl;        -   -heteroaryl;        -   -heterocyclyl;        -   -alkenyl;        -   —R₄-aryl;        -   —R₄-heteroaryl; and        -   —R₄-heterocyclyl;    -   R₂ is selected from the group consisting of:        -   -hydrogen;        -   -alkyl;        -   -alkenyl;        -   -aryl;        -   -heteroaryl;        -   -heterocyclyl;        -   -alkyl-Y-alkyl;        -   -alkyl-Y-alkenyl;        -   -alkyl-Y-aryl; and        -   -alkyl or alkenyl substituted by one or more substituents            selected from the group consisting of:            -   —OH;            -   -halogen;            -   —N(R₃)₂;            -   —CO—N(R₃)₂;            -   —CO—C₁₋₁₀alkyl;            -   —CO—O—C₁₋₁₀alkyl;            -   —N₃;            -   -aryl;            -   -heteroaryl;            -   -heterocyclyl;            -   —CO-aryl; and            -   —CO-heteroaryl;    -   each R₃ is independently H or C₁₋₁₀ alkyl;    -   each R₄ is independently alkyl or alkenyl;    -   each Y is independently —O— or —S(O)₀₋₂—;    -   n is 0 to 4; and    -   each R present is independently selected from the group        consisting of C₁₋₁₀ alkyl, C₁₋₁₀ alkoxy, hydroxy, halogen and        trifluoromethyl;        or a pharmaceutically acceptable salt thereof.        Preparation of the Compounds

Compounds of the invention can be prepared according to Reaction SchemeI where R, R₁, R₂, X and n are as defined above.

In step (1) of Reaction Scheme I a 4-chloro-3-nitroquinoline of FormulaX is reacted with an amine of formula HO—X—NH₂ to provide a3-nitroquinolin-4-amine of Formula XI. The reaction can be carried outby adding the amine to a solution of a compound of Formula X in asuitable solvent such as chloroform or dichloromethane in the presenceof triethylamine and optionally heating. Many quinolines of Formula Xare known compounds (see for example, U.S. Pat. No. 4,689,338 andreferences cited therein). Many amines of formula HO—X—NH₂ arecommercially available; others can be readily prepared using knownsynthetic routes.

In step (2) of Reaction Scheme I a 3-nitroquinolin-4-amine of Formula XIis chlorinated to provide a 3-nitroquinolin-4-amine of Formula XII.Conventional chlorinating agents can be used. Preferably the reaction iscarried out by combining a compound of Formula XI with thionyl chloridein a suitable solvent such as dichloromethane and heating. Alternativelythe reaction may be run neat.

In step (3) of Reaction Scheme I a 3-nitroquinolin-4-amine of FormulaXII is reduced to provide a quinoline-3,4-diamine of Formula XIII.Preferably, the reduction is carried out using a conventionalheterogeneous hydrogenation catalyst such as platinum on carbon. Thereaction can conveniently be carried out on a Parr apparatus in asuitable solvent such as toluene.

In step (4) of Reaction Scheme I a quinoline-3,4-diamine of Formula XIIIis reacted with a carboxylic acid or an equivalent thereof to provide a1H-imidazo[4,5-c]quinoline of Formula XIV. Suitable equivalents to acarboxylic acid include orthoesters, and 1,1-dialkoxyalkyl alkanoates.The carboxylic acid or equivalent is selected such that it will providethe desired R₂ substituent in a compound of Formula XIV. For example,triethyl orthoformate will provide a compound where R₂ is hydrogen andtrimethyl orthovalerate will provide a compound where R₂ is butyl. Thereaction can be run in the absence of solvent or in an inert solventsuch as toluene. The reaction is run with sufficient heating to driveoff any alcohol or water formed as a byproduct of the reaction.Optionally a catalyst such as pyridine hydrochloride can be included.

Alternatively, step (4) can be carried out by (i) reacting the diamineof Formula XIII with an acyl halide of Formula R₂C(O)Cl or R₂C(O)Br andthen (ii) cyclizing. In part (i) the acyl halide is added to a solutionof the diamine in a suitable solvent such as pyridine. The reaction canbe carried out at ambient temperature. In part (ii) the product of part(i) is heated in pyridine in the presence of pyridine hydrochloride.

In step (5) of Reaction Scheme I a 1H-imidazo[4,5-c]quinoline of FormulaXIV is oxidized to provide a 1H-imidazo[4,5-c]quinoline-5N-oxide ofFormula XV using a conventional oxidizing agent capable of formingN-oxides. Preferably a solution of a compound of Formula XIV in asuitable solvent such as chloroform or dichloromethane is treated with3-chloroperoxybenzoic acid at ambient temperature.

In step (6) of Reaction Scheme I a 1H-imidazo[4,5-c]quinoline-5N-oxideof Formula XV is aminated to provide a 1H-imidazo[4,5-c]quinolin-4-amineof Formula XVI. Step (6) involves (i) reacting a compound of Formula XVwith an acylating agent and then (ii) reacting the product with anaminating agent. Part (i) of step (6) involves reacting an N-oxide ofFormula XV with an acylating agent. Suitable acylating agents includealkyl- or arylsulfonyl chlorides (e.g., benezenesulfonyl chloride,methanesulfonyl chloride, p-toluenesulfonyl chloride). Arylsulfonylchlorides are preferred. Para-toluenesulfonyl chloride is mostpreferred. Part (ii) of step (6) involves reacting the product of part(i) with an excess of an aminating agent. Suitable aminating agentsinclude ammonia (e.g., in the form of ammonium hydroxide) and ammoniumsalts (e.g., ammonium carbonate, ammonium bicarbonate, ammoniumphosphate). Ammonium hydroxide is preferred. The reaction is preferablycarried out by dissolving the N-oxide of Formula XV in an inert solventsuch as dichloromethane or chloroform, adding the aminating agent to thesolution, and then slowly adding the acylating agent.

In step (7) of Reaction Scheme I a 1H-imidazo[4,5-c]quinolin-4-amine ofFormula XVI is reacted with a compound of Formula R₁—SNa to provide a1H-imidazo[4,5-c]quinolin-4-amine of Formula XVII which is a subgenus ofFormula I. The reaction can be carried out by combining a compound ofFormula XVI with a compound of formula R₁SNa in a suitable solvent suchas N,N-dimethylformamide or dimethyl sulfoxide and heating (60–80° C.).The product or a pharmaceutically acceptable salt thereof can beisolated using conventional methods.

In step (8) of Reaction Scheme I a 1H-imidazo[4,5-c]quinolin-4-amine ofFormula XVII is oxidized using a conventional oxidizing agent to providea 1H-imidazo[4,5-c]quinolin-4-amine of Formula XVIII which is a subgenusof Formula I. Preferably a solution of a compound of Formula XVII in asuitable solvent such as chloroform or dichloromethane is treated with3-chloroperoxybenzoic acid at ambient temperature. The degree ofoxidation is controlled by adjusting the amount of 3-chloroperoxybenzoicacid used in the reaction; i.e., using approximately one equivalent willprovide the sulfoxide whereas using two equivalents will provide thesulfone. The product or a pharmaceutically acceptable salt thereof canbe isolated using conventional methods.

Compounds of the invention can be prepared according to Reaction SchemeII where R, R₁, R₂, X and n are as defined above.

In step (1) of Reaction Scheme II a 3-nitroquinolin-4-amine of FormulaXII is reacted with a compound of the Formula R₁—SNa using the method ofstep (7) of Reaction Scheme I to provide a 3-nitroquinolin-4-amine ofFormula XIX.

In step (2) of Reaction Scheme II a 3-nitroquinolin-4-amine of FormulaXIX is reduced using the method of step (3) of Reaction Scheme I toprovide a quinoline-3,4-diamine of Formula XX.

In step (3) of Reaction Scheme II a quinoline-3,4-diamine of Formula XXis cyclized using the method of step (4) of Reaction Scheme I to providea 1H-imidazo[4,5-c]quinoline of Formula XXI.

In step (4) of Reaction Scheme II a 1H-imidazo[4,5-c]quinoline ofFormula XXI is oxidized to provide a 1H-imidazo[4,5-c]quinolin-5N-oxideof Formula XXII using a conventional oxidizing agent. Preferably asolution of a compound of Formula XXI in a suitable solvent such aschloroform or dichloromethane is treated with at least three equivalentsof 3-chloroperoxybenzoic acid at ambient temperature.

In step (5) of Reaction Scheme II a 1H-imidazo[4,5-c]quinolin-5N-oxideof Formula XXII is aminated using the method of step (6) of ReactionScheme I to provide a 1H-imidazo[4,5-c]quinolin-4-amine of Formula XVIIIwhich is a subgenus of Formula I. The product or a pharmaceuticallyacceptable salt thereof can be isolated using conventional methods.

Compounds of the invention can be prepared according to Reaction SchemeIII where R, R₁, R₂, X and n are as defined above.

In step (1) of Reaction Scheme III a 3-nitro-4-amino-quinolin-1-ylalcohol of Formula XI is protected with a tert-butyldimethylsilyl groupusing conventional methods. Preferably a compound of Formula XI iscombined with tert-butyldimethylsilyl chloride in a suitable solventsuch as chloroform in the presence of triethylamine and a catalyticamount of 4-dimethylaminopyridine.

In step (2) of Reaction Scheme III a protected3-nitro-4-amino-quinolin-1-yl alcohol of Formula XIII is reduced usingthe method of step (3) of Reaction Scheme I to provide a protected3,4-diamino-quinolin-1-yl alcohol of Formula XXIV.

In step (3) of Reaction Scheme III a protected 3,4-diamino-quinolin-1-ylalcohol of Formula XXIV is cyclized using the method of step (4) ofReaction Scheme I to provide a 1H-imidazo[4,5-c]quinoline of FormulaXXV.

In step (4) of Reaction Scheme III a 1H-imidazo[4,5-c]quinoline ofFormula XXV is oxidized using the method of step (5) of Reaction SchemeI to provide a 1H-imidazo[4,5-c]quinolin-5N-oxide of Formula XXVI.

In step (5) of Reaction Scheme III a 1H-imidazo[4,5-c]quinolin-5N-oxideof Formula XXVI is aminated using the method of step (6) of ReactionScheme I to provide a 1H-imidazo[4,5-c]quinolin-4-amine of FormulaXXVII.

In step (6) of Reaction Scheme III the protecting group is removed froma 1H-imidazo[4,5-c]quinolin-4-amine of Formula XXVII to provide a1H-imidazo[4,5-c]quinolin-4-amine of Formula XXVIII. Preferably asolution of a compound of Formula XXVII in a suitable solvent such astetrahydrofuran is treated with tetrabutylammonium fluoride. Somecompounds of Formula XXVIII are known, see for example, Gerster, U.S.Pat. No. 4,689,338 and Gerster et al., U.S. Pat. No. 5,605,899.

In step (7) of Reaction Scheme III a 1H-imidazo[4,5-c]quinolin-4-amineof Formula XXVIII is chlorinated using conventional methods to provide a1H-imidazo[4,5-c]quinolin-4-amine of Formula XVI. A compound of FormulaXXVIII can be heated neat with thionyl chloride. Alternatively,phosphorous oxychloride can be added in a controlled fashion to asolution of a compound of Formula XXVIII in a suitable solvent such asN,N-dimethylformamide in the presence of triethylamine.

Steps (8) and (9) of Reaction Scheme III can be carried out in the samemanner as steps (7) and (8) respectively of Reaction Scheme I.

Compounds of the invention can be prepared according to Reaction SchemeIV where R, R₁, R₂, X and n are as defined above and BOC istert-butoxycarbonyl.

In step (1) of Reaction Scheme IV the hydroxy group of a6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-1-yl alcohol of FormulaXXIX is protected with a tert-butyldimethylsilyl group using the methodof step (1) of Reaction Scheme III. Compounds of Formula XXIX are knownor can be prepared using known synthetic methods, see for example,Nikolaides, et al., U.S. Pat. No. 5,352,784 and Lindstrom, U.S. Pat. No.5,693,811 and references cited therein.

In step (2) of Reaction Scheme IV the amino group of a1H-imidazo[4,5-c]quinolin-4-amine of Formula XXX is protected usingconventional methods to provide a protected 1H-imidazo[4,5-c]quinolineof Formula XXXI. Preferably a compound of Formula XXX is treated withdi-tert-butyl dicarbonate in a suitable solvent such as tetrahydrofuranin the presence of triethylamine and 4-dimethylaminopyridine. Thereaction cap be run at an elevated temperature (60° C.).

In step (3) of Reaction Scheme IV the tert-butyldimethylsilyl protectinggroup of a compound of Formula XXXI is removed using the method of step(6) of Reaction Scheme III to provide a 1H-imidazo[4,5-c]quinolin-1ylalcohol of Formula XXXII.

In step (4) of Reaction Scheme IV a 1H-imidazo[4,5-c]quinolin-1ylalcohol of Formula XXXII is converted to a methanesulfonate of FormulaXXXIII. Preferably a solution of a compound of Formula XXXII in asuitable solvent such as dichloromethane is treated with methanesulfonylchloride in the presence of triethylamine. The reaction can be run at areduced temperature (−10° C.).

In step (5) of Reaction Scheme IV a methanesulfonate of Formula XXXIIIis reacted with a thiol of formula R₁SH to provide a thioether ofFormula XXXIV. Preferably a solution of a compound of Formula XXXIII ina suitable solvent such as N,N-dimethylformamide is treated with thethiol in the presence of triethylamine. The reaction can be run at anelevated temperature (80° C.).

In step (6) of Reaction Scheme IV the tert-butoxycarbonyl protectinggroups are removed by hydrolysis under acidic conditions to provide a1H-imidazo[4,5]quinolin-4-amine of Formula XXXV which is a subgenus ofFormula II. Preferably a solution of a compound of Formula XXXIV in asuitable solvent such as dichloromethane is treated at ambienttemperature with a solution of hydrochloric acid in dioxane. The productor a pharmaceutically acceptable salt thereof can be isolated usingconventional methods.

In step (7) of Reaction Scheme IV a thioether of Formula XXXV isoxidized using the method of step (8) of Reaction Scheme I to provide asulfone or sulfoxide of Formula XXXVI which is a subgenus of Formula II.The product or a pharmaceutically acceptable salt thereof can beisolated using conventional methods.

Compounds of the invention can be prepared according to Reaction SchemeV where R, R₁, R₂, X and n are as defined above.

In step (1) of Reaction Scheme V a6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-1-yl alcohol of FormulaXXIX is chlorinated using the method of step (7) of Reaction Scheme IIIto provide a compound of Formula XXXVII.

In step (2) of Reaction Scheme V a compound of Formula XXXVII is reactedwith a compound of formula R₁—SNa using the method of step (7) ofReaction Scheme I to provide a thioether of Formula XXXV which is asubgenus of Formula II. The product or a pharmaceutically acceptablesalt thereof can be isolated using conventional methods.

In step (3) of Reaction Scheme V a thioether of Formula XXXV is oxidizedusing the method of step (8) of Reaction Scheme I to provide a sulfoneor sulfoxide of Formula XXXVI which is a subgenus of Formula II. Theproduct or a pharmaceutically acceptable salt thereof can be isolatedusing conventional methods.

As used herein, the terms “alkyl”, “alkenyl” and the prefix “alk-” areinclusive of both straight chain and branched chain groups and of cyclicgroups, i.e. cycloalkyl and cycloalkenyl. Unless otherwise specified,these groups contain from 1 to 20 carbon, atoms, with alkenyl groupscontaining from 2 to 20 carbon atoms. Preferred groups have a total ofup to 10 carbon atoms. Cyclic groups can be monocyclic or polycyclic andpreferably have from 3 to 10 ring carbon atoms. Exemplary cyclic groupsinclude cyclopropyl, cyclopropylmethyl, cyclopentyl, cyclohexyl andadamantyl.

In addition, the alkyl and alkenyl portions of —X— groups can beunsubstituted or substituted by one or more substituents, whichsubstituents are selected from the groups consisting of alkyl, alkenyl,aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, andheterocyclylalkyl.

The term “haloalkyl” is inclusive of groups that are substituted by oneor more halogen atoms, including perfluorinated groups. This is alsotrue of groups that include the prefix “halo-”, Examples of suitablehaloalkyl groups are chloromethyl, trifluoromethyl, and the like.

The term “aryl” as used herein includes carbocyclic aromatic rings orring systems. Examples of aryl groups include phenyl, naphthyl,biphenyl, fluorenyl and indenyl. The term “heteroaryl” includes aromaticrings or ring systems that contain at least one ring hetero atom (e.g.,O, S, N). Suitable heteroaryl groups include furyl, thienyl, pyridyl,quinolinyl, isoquinolinyl, indolyl, isoindolyl, triazolyl, pyrrolyl,tetrazolyl, imidazolyl, pyrazolyl, oxazolyl, thiazolyl, benzofuranyl,benzothiophenyl, carbazolyl, benzoxazolyl, pyrimidinyl benzimidazolyl,quinoxalinyl, benzothiazolyl, naphthyridinyl, isoxazolyl, isothiazolyl,purinyl, quinazolinyl, and so on.

“Heterocyclyl” includes non-aromatic rings or ring systems that containat least one ring hetero atom (e.g., O, S, N) and includes all of thefully-saturated and partially unsaturated derivatives of the abovementioned heteroaryl groups. Exemplary heterocyclic groups includepyrrolidinyl, tetrahydrofuranyl, morpholinyl, thiomorpholinyl,piperidinyl, piperazinyl, thiazolidinyl, imidazolidinyl,isothiazolidinyl, and the like.

The aryl, heteroaryl, and heterocyclyl groups can be unsubstituted orsubstituted by one or more substituents independently selected from thegroup consisting of alkyl, alkoxy, alkylthio, haloalkyl, haloalkoxy,haloalkylthio, halogen, nitro, hydroxy, mercapto, cyano, carboxy,formyl, aryl, aryloxy, arylthio, arylalkoxy, arylalkylthio, heteroaryl,heteroaryloxy, heteroarylthio, heteroarylalkoxy, heteroarylalkylthio,amino, alkylamino, dialkylamino, heterocyclyl, heterocycloalkyl,alkylcarbonyl, alkenylcarbonyl, alkoxycarbonyl, haloalkylcarbonyl,haloalkoxycarbonyl, alkylthiocarbonyl, arylcarbonyl, heteroarylcarbonyl,aryloxycarbonyl, heteroaryloxycarbonyl, arylthiocarbonyl,heteroarylthiocarbonyl, alkanoyloxy, alkanoylthio, alkanoylamino,arylcarbonyloxy, arylcarbonylthio, alkylaminosulfonyl, alkylsulfonyl,arylsulfonyl, heteroarylsulfonyl, aryldiazinyl, alkylsulfonylamino,arylsulfonylamino, arylalkylsulfonylamino, alkylcarbonylamino,alkenylcarbonylamino, arylcarbonylamino, arylalkylcarbonylamino,heteroarylcarbonylamino, heteroarylalkycarbonylamino,alkylsulfonylamino, alkenylsulfonylamino, arylsulfonylamino,arylalkylsulfonylamino, heteroarylsulfonylamino,heteroarylalkylsulfonylamino, alkylaminocarbonylamino,alkenylaminocarbonylamino, arylaminocarbonylamino,arylalkylaminocarbonylamino, heteroarylaminocarbonylamino,heteroarylalkylcarbonylamino, and, in the case of heterocyclyl, oxo. Ifany other groups are identified as being “substituted” or “optionallysubstituted”, then those groups can also be substituted by one or moreof the above enumerated substituents.

Certain substituents are generally preferred. For example, preferred Xgroups include ethylene and n-butylene and preferred R₁ groups are alkyland aryl, with phenyl or substituted phenyl a preferred aryl group.Preferably no R substituents are present (i.e., n is 0). Preferred R₂groups include hydrogen, alkyl groups having 1 to 4 carbon atoms (i.e.,methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, andcyclopropylmethyl), methoxyethyl, and ethoxymethyl. One or more of thesepreferred substituents, if present, can be present in the compounds ofthe invention in any combination.

The invention is inclusive of the compounds described herein in any oftheir pharmaceutically acceptable forms, including isomers (e.g.,diastereomers and enantiomers), salts, solvates, polymorphs, and thelike. In particular, if a compound is optically active, the inventionspecifically includes each of the compound's enantiomers as well asracemic mixtures of the enantiomers.

Pharmaceutical Compositions and Biological Activity

Pharmaceutical compositions of the invention contain a therapeuticallyeffective amount of a compound of the invention as described above incombination with a pharmaceutically acceptable carrier.

The term “a therapeutically effective amount” means an amount of thecompound sufficient to induce a therapeutic effect, such as cytokineinduction, antitumor activity, and/or antiviral activity. Although theexact amount of active compound used in a pharmaceutical composition ofthe invention will vary according to factors known to those of skill inthe art, such as the physical and chemical, nature of the compound, thenature of the carrier, and the intended dosing regimen, it isanticipated that the compositions of the invention will containsufficient active ingredient to provide a dose of about 100 ng/kg toabout 50 mg/kg, preferably about 10 μg/kg to about 5 mg/kg, of thecompound to the subject. Any of the conventional dosage forms may beused, such as tablets, lozenges, parenteral formulations, syrups,creams, ointments, aerosol formulations, transdermal patches,transmucosal patches and the like.

The compounds of the invention can be administered as the singletherapeutic agent in the treatment regimen, or the compounds of theinvention may be administered in combination with one another or withother active agents, including additional immune response modifiers,antivirals, antibiotics, etc.

The compounds of the invention have been shown to induce the productionof certain cytokines in experiments performed according to the tests setforth below. These results indicate that the compounds are useful asimmune response modifiers that can modulate the immune response in anumber of different ways, rendering them useful in the treatment of avariety of disorders.

Cytokines whose production may be induced by the administration ofcompounds according to the invention generally include interferon-α(IFN-α) and/or tumor necrosis factor-α (TNF-α) as well as certaininterleukins (IL). Cytokines whose biosynthesis may be induced bycompounds of the invention include IFN-α, TNF-α, IL-1, IL-6, IL-10 andIL-12, and a variety of other cytokines. Among other effects, these andother cytokines can inhibit virus production and tumor cell growth,making the compounds useful in the treatment of viral diseases andtumors. Accordingly, the invention provides a method of inducingcytokine biosynthesis in an animal comprising administering an effectiveamount of a compound or composition of the invention to the animal.

Certain compounds of the invention have been found to preferentiallyinduce the expression of IFN-α in a population of hematopoietic cellssuch as PBMCs (peripheral blood mononuclear cells) containing pDC2 cells(precursor dendritic cell-type 2) without concomitant production ofsignificant levels of inflammatory cytokines.

In addition to the ability to induce the production of cytokines, thecompounds of the invention affect other aspects of the innate immuneresponse. For example, natural killer cell activity may be stimulated,an effect that may be due to cytokine induction. The compounds may alsoactivate macrophages, which in turn stimulates secretion of nitric oxideand the production of additional cytokines. Further, the compounds maycause proliferation and differentiation of B-lymphocytes.

Compounds of the invention also have an effect on the acquired immuneresponse. For example, although there is not believed to be any directeffect on T cells or direct induction of T cell cytokines, theproduction of the T helper type 1 (Th1) cytokine IFN-γ is inducedindirectly and the production of the T helper type 2 (Th2) cytokinesIL-4, IL-5 and IL-13 are inhibited upon administration of the compounds.This activity means that the compounds are useful in the treatment ofdiseases where upregulation of the Th1 response and/or downregulation ofthe Th2 response is desired. In view of the ability of compounds of theinvention to inhibit the Th2 immune response, the compounds are expectedto be useful in the treatment of atopic diseases, e.g., atopicdermatitis, asthma, allergy, allergic rhinitis; systemic lupuserythematosis; as a vaccine adjuvant for cell mediated immunity; andpossibly as a treatment for recurrent fungal diseases and chlamydia.

The immune response modifying effects of the compounds make them usefulin the treatment of a wide variety of conditions. Because of theirability to induce the production of cytokines such as IFN-α and/orTNF-α, the compounds are particularly useful in the treatment of viraldiseases and tumors. This immunomodulating activity suggests thatcompounds of the invention are useful in treating diseases such is, butnot limited to, viral diseases including genital warts; common warts;plantar warts; Hepatitis B; Hepatitis C; Herpes Simplex Virus Type I andType II; molluscum contagiosum; variola, particularly variola major;HIV; CMV; VZV; rhinovirus; adenovirus; influenza; and para-influenza;intraepithelial neoplasias such as cervical intraepithelial neoplasia;human papillomavirus (HPV) and associated neoplasias; fungal diseases,e.g. candida, aspergillus, and cryptococcal meningitis; neoplasticdiseases, e.g., basal cell carcinoma, hairy cell leukemia, Kaposi'ssarcoma, renal cell carcinoma, squamous cell carcinoma, myelogenousleukemia, multiple myeloma melanoma, non-Hodgkin's lymphoma, cutaneousT-cell lymphoma, and other cancers; parasitic diseases, e.g.pneumocystis carnii, cryptosporidiosis, histoplasmosis, toxoplasmosis,trypanosome infection, and leishmaniasis; and bacterial infections,e.g., tuberculosis, and mycobacterium avium. Additional diseases orconditions that can be treated using the compounds of the inventioninclude actinic keratosis; eczema; eosinophilia; essentialthrombocythaemia; leprosy; multiple sclerosis; Ommen's syndrome; discoidlupus; Bowen's disease; Bowenoid papulosis; alopecia areata; theinhibition of Keloid formation after surgery and other types ofpost-surgical scars. In addition, these compounds could enhance orstimulate the healing of wounds, including chronic wounds. The compoundsmay be useful for treating the opportunistic infections and tumors thatoccur after suppression of cell mediated immunity in, for example,transplant patients, cancer patients and HIV patients.

An amount of a compound effective to induce cytokine biosynthesis is anamount sufficient to cause one or more cell types, such as monocytes,macrophages, dendritic cells and B-cells to produce an amount of one ormore cytokines such as, for example, IFN-α, TNF-α, IL-1, IL-6, IL-10 andIL-12 that is increased over the background level of such cytokines. Theprecise amount will vary according to factors known in the art but isexpected to be a dose of about 100 ng/kg to about 50 mg/kg, preferablyabout 10 μg/kg to about 5 mg/kg. The invention also provides a method oftreating a viral infection in an animal and a method of treating aneoplastic disease in an animal comprising administering an effectiveamount of a compound or composition of the invention to the animal. Anamount effective to treat or inhibit a viral infection is an amount thatwill cause a reduction in one or more of the manifestations of viralinfection, such as viral lesions, viral load, rate of virus production,and mortality as compared to untreated control animals. The preciseamount will vary according to factors known in the art but is expectedto be a dose of about 100 ng/kg to about 50 mg/kg, preferably about 10μg/kg to about 5 mg/kg. An amount of a compound effective to treat aneoplastic condition is an amount that will cause a reduction in tumorsize or in the number of tumor foci. Again, the precise amount will varyaccording to factors known in the art but is expected to be a dose ofabout 100 ng/kg to about 50 mg/kg, preferably about 10 μg/kg to about 5mg/kg.

The invention is further described by the following examples, which areprovided for illustration only and are not intended to be limiting inany way.

EXAMPLE 12-butyl-1-[4-(phenylthio)butyl]-1H-imidazo[4,5-c]quinolin-4-amine

Part A

A round bottom flask was charged with a magnetic stir bar,4-chloro-3-nitroquinoline (109.70 g, 525.87 mmol) and dichloromethane(500 mL). To the solution was added triethylamine (79.82 g, 788.81 mmol)and 4-amino-1-butanol (46.87 g, 525.87 mmol) to give a homogeneous, darkyellow solution. The reaction was judged to be complete after heating atreflux for 30 minutes. The solution was cooled and then partitionedbetween chloroform and saturated aqueous ammonium chloride. The layerswere separated and the aqueous layer was extracted with chloroform (1×).The organic layers were combined and then concentrated under reducedpressure to afford of 4-[(3-nitroquinolin)amino]butan-1-ol (104.67 g,400.60 mmol) as a dark yellow solid. This material was used withoutfurther purification.

Part B

A round bottom flask was charged with a magnetic stir bar,4-[(3-nitroquinolin-4-yl)amino]butan-1-ol (5.0 g, 19.14 mmol),triethylamine (2.91 g, 28.71 mmol), tert-butyldimethylsilyl chloride(3.75 g, 24.9 mmol), 4-dimethylaminopyridine (0.10 g) and chloroform (40mL) to give a dark yellow solution. The reaction was judged was tocomplete after stirring at ambient temperature for 2 hours. The solutionwas partitioned between ethyl acetate and saturated aqueous ammoniumchloride. The layers were separated and the organic layer was washedwith saturated aqueous sodium bicarbonate, dried over anhydrous sodiumsulfate, filtered and then concentrated under reduced pressure to affordN-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)-3-nitroquinolin-4-amine(6.05 g, 16.11 mmol) as a yellow-green solid. This material was usedwithout further purification. MS (CI) for C₁₉H₂₉N₃O₃Si m/z 376 (MH⁺),342, 210.

Part C

A Parr vessel was charged withN-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)-3-nitroquinolin-4-amine(6.05 g, 16.11 mmol), 5% platinum on carbon (3.0 g), and toluene (32mL). The vessel was placed on a Parr shaker and pressurized to 50 psi(3.5 Kg/cm²) hydrogen. After shaking for one hour, more catalyst (3.0 g)and toluene (15 mL) were added and the vessel was pressurized to 50 psi(3.5 Kg/cm²) hydrogen and shaking continued. The reaction was judged tobe complete after one hour. The catalyst was removed by filtrationthrough fluted paper. The filter cake was washed with toluene (50 mL)and the filtrates were combined. The volatiles were removed underreduced pressure to affordN-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)quinoline-3,4-diamine (5.57g, 16.11 mmol) as a dark oil. The material was used without furtherpurification.

Part D

A round bottom flask was charged with a magnetic stir bar,N-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)quinoline-3,4-diamine (5.57g, 16.11 mmol), trimethyl orthovalerate (5.23 g, 32.22 mmol) and toluene(47 mL). The reaction was heated to maintain a reflux that brought abouta slow distillation to facilitate removal of the methanol byproduct. Thereaction was judged to be complete after 15 hours at reflux. Thereaction was cooled and the volatiles were removed under reducedpressure to afford of2-butyl-1-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)-1H-imidazo[4,5-c]quinoline(4.65 g, 11.30 mmol) as a thick, dark brown oil. The material was usedwithout further purification. MS (CI) for C₂₄H₃₇N₃OSi m/z 412 (MH⁺),298.

Part E

A round bottom flask was charged with a magnetic stir bar,2-butyl-1-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)-1H-imidazo[4,5-c]quinoline(4.65 g, 11.30 mmol) and chloroform (57 mL). Solid 3-chloroperbenzoicacid (2.78 g, 12.43 mmol) was added portion wise to the solution over 15minutes and the reaction was stirred at ambient temperature for 1 hour.More 3-chloroperbenzoic acid (0.5 g, 2.9 mmol) was added and after 30minutes the starting material was completely consumed. The solution waspartitioned between chloroform and aqueous saturated sodium bicarbonate.The layers were separated. The organic layer was washed with saturatedaqueous sodium bicarbonate and brine, dried over anhydrous sodiumsulfate, filtered and then concentrated under reduced pressure to afford2-butyl-1-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)-1H-imidazo[4,5-c]quinoline-5N-oxide(4.83 g, 11.30 mmol) as a dark oil. The material was used withoutfurther purification.

Part F

A round bottom-flask was charged with a magnetic stir bar,2-butyl-1-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)-1H-imidazo[4,5-c]quinoline-5N-oxide(11.30 mmol) and anhydrous dimethyl formamide (57 mL) under a nitrogenatmosphere. Phosphorus oxychloride (1.91 g, 12.43 mmol) was added to thereaction mixture in a drop wise fashion to give a homogeneous solutionafter complete addition. The reaction was judged to be complete afterstirring for 1.5 hours at ambient temperature and was then partitionedbetween dichloromethane and saturated aqueous sodium bicarbonate. Thelayers were separated and the organic portion was washed with aqueoussaturated sodium bicarbonate and brine, dried over anhydrous sodiumsulfate, filtered and then concentrated under reduced pressure to afford2-butyl-4-chloro-1-(4-chlorobutyl)-1H-imidazo[4,5-c]quinoline (3.65 g,10.42 mmol) as a dark brown solid. The material was used without furtherpurification. MS (CI) for C₁₈H₂₁Cl₂N₃ m/z 350 (MH⁺); 314.

Part G

A round bottom flask was charged with a magnetic stir bar,2-butyl4-chloro-1-(4-chlorobutyl)-1H-imidazo[4,5-c]quinoline (1.18 g,3.37 mmol), benzenethiol (0.56 g, 5.05 mmol), triethylamine (0.68 g,6.74 mmol), and dimethyl formamide (15 mL) under a nitrogen atmosphere.The reaction mixture was heated to 80° C. to give a homogeneous solutionthat was maintained at 80° C. for 2.5 hours. HPLC analysis indicated nostarting material and a 3:1 mixture of2-butyl4-chloro-1-[4-(phenylthio)butyl]-1H-imidazo[4,5-c]quinoline and2-butyl4-(phenylthio)-1-[4-(phenylthio)butyl]-1H-imidazo[4,5-c]quinoline.The solution was cooled and then partitioned between ethyl acetate andaqueous saturated sodium bicarbonate. The layers were separated and theorganic layer was washed with aqueous saturated sodium bicarbonate andbrine, dried over anhydrous sodium sulfate, filtered and thenconcentrated under reduced pressure to afford a 3:1 mixture of theproducts named above (1.43 g). The material was used without furtherpurification.

Part H

A 3:1 mixture of2-butyl-4-chloro-1-[4-(phenylthio)butyl]-1H-imidazo[4,5-c]quinoline to2-butyl-4-(phenylthio)-1-[4-(phenylthio)butyl]-1H-imidazo[4,5-c]quinoline(1.38 g) and a solution of 7% ammonia in methanol (30 mL) were combinedin a bomb and heated to 150° C. The reaction was judged to be completeafter 5 hours. The volatiles were removed under reduced pressure and theresulting residue was stirred in water and made basic (pH 10) with solidsodium carbonate. The aqueous mixture was extracted with chloroform(3×). The combined organic layers were washed with saturated aqueoussodium bicarbonate and brine, dried over anhydrous sodium sulfate,filtered and then concentrated under reduced pressure to afford a yellowcrystalline solid. The solid (0.8 g) was dissolved in ethyl acetate (50mL) and brought to reflux. Activated charcoal (0.4 g) was added; theresulting mixture was heated at reflux for 5 minutes and then thecharcoal was removed by filtration through fluted paper to provide acolorless solution. The solution was concentrated under reduced pressureto give a solid that was recrystallized from ethyl acetate and hexanesto provide2-butyl-1-[4-(phenylthio)butyl]-1H-imidazo[4,5-c]quinolin-4-amine (0.51g, 1.25 mmol) as white needles, m.p. 118–120° C.

Analysis. Calculated for C₂₄H₂₈N₄S: % C 71.25; % H, 6.98; % N, 13.85.Found % C 71.12; % H, 6.81; % N, 13.62.

¹H-NMR (300 MHz, DMSO) δ 8.02 (d, J=8.3 Hz, 1H), δ 7.61 (d, J=8.3 Hz,1H), δ 7.41 (t, J=8.3 Hz, 1H), δ 7.16–7.30 (m, 6H), δ 6.46 (bs, 2H), δ4.52 (t, J=7.6 Hz, 2H), δ 3.02 (t, J=7.3 Hz, 2H), δ 2.89 (t, J=7.8 Hz,2H), δ 1.95 (m, 2H), δ 1.75 (m, 4H), δ1.43 (sextet, J=7.3 Hz, 2H), δ0.94 (t, J=7.3 Hz, 3H)

MS (CI) for C₂₄H₂₈N₄S m/z 405 (MH⁺), 282, 241

EXAMPLE 22-butyl-1-[2-(phenylthio)ethyl]-6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-4-aminehydrochloride

Part A

A round bottom flask was charged with a magnetic stir bar,2-(4-amino-2-butyl-6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-1-yl)ethanol(1.0 g, 3.47 mmol), tert-butyldimethylsilyl chloride (1.62 g, 10.75mmol), triethylamine (1.58 g, 15.62 mmol), 4-dimethylaminopyridine (0.1g), and chloroform (30 mL) to give a heterogeneous reaction mixture. Thereaction was judged to be complete after stirring at 60° C. for 2 hours.The solution was partitioned between ethyl acetate and saturated aqueousammonium chloride. The layers were separated and the organic layer waswashed with aqueous saturated sodium bicarbonate and brine, dried overanhydrous sodium sulfate, filtered and then concentrated under reducedpressure to afford a 3:1 mixture of2-butyl-1-(2-{[tert-butyl(dimethyl)silyl]oxy}ethyl)-6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-4-amineand2-butyl-N-[tert-butyl(dimethyl)silyl]-1-(2-{[tert-butyl(dimethyl)silyl]oxy}ethyl)-6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-4-amine(1.79 g) as a dark brown oil. The material was used without furtherpurification.

Part B

A round bottom flask was charged with a magnetic stir bar, a 3:1 mixtureof2-butyl-1-(2-{[tert-butyl(dimethyl)silyl]oxy}ethyl)-6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-4-amineand2-butyl-N-[tert-butyl(dimethyl)silyl]-1-(2-{[tert-butyl(dimethyl)silyl]oxy}ethyl)-6,7,8,9-tetrahydro-1H-imidazo[4,5]quinolin-4-amine(1.6 g) and a 1 M solution of acetic acid in dichloromethane (85 mL) toprovide a homogenous solution. The reaction was judged to be completeafter stirring at ambient temperature for 30 minutes. The solution waspartitioned between chloroform and brine. The layers were separated andthe organic layer was washed with aqueous saturated sodium bicarbonateand brine, dried over anhydrous sodium sulfate, filtered and thenconcentrated under reduced pressure to afford a dark brown oil. Thematerial was purified by chromatography over silica gel (95/4/1dichloromethane/methanol/ammonium hydroxide [14.8 M in water]) toprovide2-butyl-1-(2-{[tert-butyl(dimethyl)silyl]oxy}ethyl)-6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-4-amine(1.24 g, 3.10 mmol) as a colorless oil.

Part C

A round bottom flask was charged with a magnetic stir bar,2-butyl-1-(2-{[tert-butyl(dimethyl)silyl]oxy}ethyl)-6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-4-amine(0.83 g, 2.06 mmol), di-tert-butyl dicarbonate (1.79 g, 8.24 mmol),triethylamine (0.52 g, 5.15 mmol), 4-dimethylaminopyridine (0.1 g), andanhydrous tetrahydrofuran (21 mL) under a nitrogen atmosphere. Thereaction mixture was heated to 60° C. to give a homogeneous solutionthat was maintained at 60° C. for 2.5 hours at which time the reactionwas judged to be complete. The solution was cooled to ambienttemperature and a 1 M solution of tetrabutylammonium fluoride intetrahydrofuran (2.27 mL, 2.27 mmol) was added. The reaction was judgedto be complete after stirring at ambient temperature for 30 minutes. Thesolution was partitioned between ethyl acetate and saturated aqueousammonium chloride. The layers were separated. The organic layer waswashed with saturated aqueous sodium bicarbonate and brine, dried overanhydrous sodium sulfate, filtered and then concentrated under reducedpressure to afford a light yellow solid. The material was purified bychromatography over silica gel (95/5 dichloromethane/methanol) toprovide di(tert-butyl)2-butyl-1-(2-hydroxyethyl)-6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-4-ylimidodicarbonate.(0.55 g, 1.13 mmol) as a clear gum.

Part D

A round bottom flask was charged with a magnetic stir bar,di(tert-butyl)2-butyl-1-(2-hydroxyethyl)-6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-4-ylimidodicarbonate(0.55 g, 1.13 mmol) and anhydrous dichloromethane (11 mL) under anitrogen atmosphere. The resulting homogeneous solution was cooled to−10° C. in a methanol/ice bath. To the cooled solution was addedtriethylamine (0.23 g, 2.26 mmol) and methanesulfonyl chloride (0.19 g,1.70 mmol). The reaction was judged to be complete after stirring at−10° C. for 15 minutes and was then partitioned between ethyl acetateand saturated aqueous ammonium chloride. The layers were separated. Theorganic layer was washed with saturated aqueous sodium bicarbonate andbrine, dried over anhydrous sodium sulfate, filtered and thenconcentrated under reduced pressure to afford2-{4-[bis(tert-butoxycarbonyl)amino]-2-butyl-6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-1-yl}ethylmethanesulfonate (0.61 g, 1.08 mmol) as a gummy yellow solid. Thematerial was used without further purification. MS (CI) for C₂₇H₄₂N₄O₇Sm/z 567 (MH⁺), 467, 367, 271.

Part E

A round bottom flask was charged with a magnetic stir bar,2-{4-[bis(tert-butoxycarbonyl)amino]-2-butyl-6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-1-yl}ethylmethanesulfonate (0.61 g, 1.08 mmol), benzenethiol (0.21 g, 1.88 mmol),triethylamine (0.25 g, 2:43 mmol) and anhydrous dimethyl formamide (11mL) under a nitrogen atmosphere. The reaction mixture was heated to 80°C. to give a dark yellow, homogeneous solution that was maintained at80° C. for 2.5 hours at which time the reaction was judged to becomplete. The solution was cooled and then partitioned between ethylacetate and saturated aqueous sodium bicarbonate. The layers wereseparated. The organic layer was washed with saturated aqueous sodiumbicarbonate and brine, dried over anhydrous sodium sulfate, filtered andthen concentrated under reduced pressure to afford a yellow oil. Thematerial was purified by chromatography over silica gel (95/5dichloromethane/methanol) to provide di(tert-butyl)2-butyl-1-[2-(phenylthio)ethyl]-6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-4-ylimidodicarbonate(0.54 g, 0.93 mmol) as a light yellow oil. MS (CI) for C₃₂H₄₄N₄O₄S m/z581 (MH⁺), 481, 381, 245.

Part F

A round bottom flask was charged with a magnetic stir bar,di(tert-butyl)2-butyl-1-[2-(phenylthio)ethyl]-6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-4-ylimidodicarbonate(0.50 g, 0.86 mmol), a 4 M solution of hydrochloric acid in dioxane (5mL), and dichloromethane (5 mL). The reaction was judged to be completeafter stirring at ambient temperature for 2 hours. The volatiles wereremoved under reduced pressure to afford an off white solid. Thematerial was recrystallized from acetonitrile to provide2-butyl-1-[2-(phenylthio)ethyl]-6,7,8,9-tetrahydro-1-H-imidazo[4,5-c]quinolin-4-aminehydrochloride (0.17 g, 1.30 mmol) as fluffy white needles, m.p. 237–238°C. Analysis. Calculated for C₂₂H₂₈N₄S.((H₂O)_(1/4).(HCl)₂: % C 57.70; %H, 6.71; % N, 12.23. Found % C 57.62; % H, 6.57; % N, 12.41.

¹H-NMR (300 MHz, DMSO) δ 7.81 (bs, 2H), δ 7.22–7.39 (m, 5H), δ 4.64 (t,J=6.8 Hz, 2H), δ 3.40 (t, J=6.8 Hz, 2H), δ 2.75 (m, 6H), δ 1.71 (m, 6H),δ 1.34 (sexet, J=7.3 Hz, 2H), δ 0.89 (t, J=7.3 Hz, 3H)

MS (CI) for C₂₂H₂₈N₄S (H₂O)_(1/4) (HCl)₂ m/z 381 (MH⁺), 245, 137

EXAMPLE 32-butyl-1-[4-(phenylsulfonyl)butyl]-1H-imidazo[4,5-c]quinolin-4-amine

Part A

Using the general method of Example 1 Part E2-butyl-1-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)-1H-imidazo[4,5-c]quinoline(16.0 g, 38. 87 mmol) was oxidized to2-butyl-1-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)-1H-imidazo[4,5-c]quinoline-5N-oxide(16.61 g, 38.87 mmol) which was isolated without purification as a tansolid.

Part B

A round bottom flask was charged with a magnetic stir bar,2-butyl-1-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)-1H-imidazo[4,5-c]quinoline-5N-oxide(16.61 g, 38.87 mmol), a 14.8 M solution of ammonium hydroxide in water(75 mL) and chloroform (200 mL). To the rapidly stirring solution wasadded p-toluenesulfonyl chloride (8.15 g, 42.76 mmol) in a portion wisefashion resulting in a mild exotherm. The reaction was judged to becomplete after stirring at ambient temperature for 10 minutes. Thesolution was partitioned between chloroform and aqueous saturated sodiumbicarbonate. The layers were separated. The organic layer was washedwith saturated aqueous sodium bicarbonate and brine, dried overanhydrous sodium sulfate, filtered and then concentrated under reducedpressure to afford an off-white solid. The material was triturated withethyl ether and collected by filtration to provide2-butyl-1-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)-1H-imidazo[4,5-c]quinolin-4-amine(9.3 g, 21.80 mmol) as a fine white powder. The material was usedwithout further purification.

Part C

A round bottom flask was charged with a magnetic stir bar,2-butyl-1-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)-1H-imidazo[4,5-c]quinolin-4-amine(9.2 g, 21.56 mmol), a 1M solution of tetrabutylammonium fluoride intetrahydrofuran (23.72 mL, 23.72 mmol), and anhydrous tetrahydrofuran(100 mL) to give a homogeneous, light orange solution. The reaction wasjudged to be complete after stirring at ambient temperature for 1 hour.While stirring, water (100 mL) was added and resulted in a mildexotherm. The volatiles were removed under reduced pressure until asolid precipitated out of solution. The solid was collected byfiltration and washed with water (20 mL) and acetone (20 mL) to afford awhite solid. The material was triturated with ethyl ether (50 mL) andcollected by filtration to provide4-(4-amino-2-butyl-1H-imidazo[4,5-c]quinolin-1-yl)butan-1-ol (6.12 g,19.59 mmol) as a fine white solid, m.p. 184–186° C.

Analysis. Calculated for C₁₈H₂₄N₄O: % C 69.20; % H, 7.74; % N, 17.93.Found % C 69.05; % H, 8.02; % N, 18.03.

MS (CI) for C₁₈H₂₄N₄O m/z 313((MH⁺)

Part D

A round bottom flask was charged with a magnetic stir bar,4-(4-amino-2-butyl-1H-imidazo[4,5-c]quinolin-1-yl)butan-1-ol (7.3 g,23.37 mmol), triethylamine (3.55 g, 35.06 mmol), and anhydrous dimethylformamide (93 mL) under a nitrogen atmosphere. To the stirred solutionwas added phosphorus oxychloride (3.94 g, 25.70 mmol) in a drop wisefashion resulting in an exotherm to give a dark yellow heterogeneousreaction mixture. The reaction mixture was heated to 60° C. to give ahomogeneous solution that was maintained at 60° C. for 5 hours at whichtime the starting material was completely consumed. The volatiles wereremoved under reduced pressure to give a dark brown oil. The materialwas partitioned between chloroform and saturated aqueous sodiumbicarbonate. The layers were separated and the aqueous layer wasextracted with chloroform (1×). The organic layers were combined and thevolatiles removed under reduced pressure to afford a 2:1 mixture ofN-[2-butyl-1-(4-chlorobutyl)-1H-imidazo[4,5-c]quinolin-4-yl]-N,N-dimethylimidoformamideand 2-butyl-1-(4-chlorobutyl)-1H-imidazo[4,5-c]quinolin-4-amine (7.70 g)as an off-white solid. The material was used without furtherpurification.

Part E

A round bottom flask was charged with a magnetic stir bar, a 2:1 mixtureofN′-[2-butyl-1H-(4-chlorobutyl)-1H-imidazo[4,5-c]quinolin-4-yl]-N,N-dimethylimidoformamideand 2-butyl-1-(4-chlorobutyl)-1H-imidazo[4,5-c]quinolin-4-amine (1.3 g),benzenesulfinic acid sodium salt (1.67 g, 10.11 mmol), and anhydrousdimethyl formamide (15 mL) under a nitrogen atmosphere. The resultingsolution was heated to 100° C. to give a homogeneous solution that wasmaintained at 100° C. for 90 hours at which time the starting materialswere completely consumed. The solution was cooled and then partitionedbetween chloroform and water. The layers were separated. The organiclayer was washed with saturated aqueous sodium bicarbonate and brine,dried over anhydrous sodium sulfate, filtered and then concentratedunder reduced pressure to afford a dark yellow gum. The material wasdissolved in methanol (20 mL) and a 4 M solution of hydrochloric acid indioxane (3.02 mL, 12.1 mmol). The light orange solution was stirred atambient temperature for 12 hours at which time the reaction was judgedto be complete. The volatiles were removed under reduced pressure togive a light yellow gum. The material was partitioned between chloroformand saturated aqueous sodium bicarbonate. The layers were separated andthe aqueous layer was extracted with chloroform (1×). The organic layerswere combined, washed with brine, dried over anhydrous sodium sulfate,filtered and then concentrated under reduced pressure to afford a lightyellow solid. The material was purified by chromatography over silicagel (95/5 dichloromethane/methanol) to give an off-white solid. Thesolid (0.63 g) was dissolved in ethyl acetate (50 mL) and brought toreflux. Activated charcoal (0.6 g) was added and the resulting-mixturewas heated at reflux for 5 minutes. The charcoal was removed byfiltration through fluted paper to provide a colorless solution. Thesolution was concentrated under reduced pressure to give a solid thatwas recrystallized from ethyl acetate and hexanes to provide2-butyl-1-[4-(phenylsulfonyl)butyl]-1H-imidazo[4,5-c]quinolin-4-amine(0.37 g, 0.85 mmol) as a white fluffy solid, m.p. 179–180° C. Analysis.Calculated for C₂₄H₂₈N₄O₂S: % C 66.03; % H, 6.46; % N, 12.83. Found % C65.88; % H, 6.49; % N, 12.76.

¹H-NMR (300 MHz, DMSO) δ 7.98 (d, J=8.3 Hz, 1H), δ 7.82 (m, 2H) δ 7.73(d, J=7.3 Hz, 1H), δ 7.62 (m, 3H) δ 7.41 (t, J=7.6 Hz, 1H), δ 7.22 (t,J=7.6 Hz, 1H), δ 6.45 (bs, 2H), δ 4.51 (t, J=7.3 Hz, 2H), δ 3.90 (t,J=7.8 Hz, 2H), δ 2.86 (t, J=7.6 Hz, 3H), δ 1.69–1.90 (m, 6H), δ 1.43(sextet, J=7.3 Hz, 2H), δ 0.95 (t, J=7.3 Hz, 3H)

MS (CI) for C₂₄H₂₈N₄O₂S m/z 437 ((MH⁺), 295

EXAMPLE 42-butyl-1-[4-(methylthio)butyl]-1H-imidazo[4,5-c]quinolin-4-amine

Part A

A round bottom flask was charged with a magnetic stir bar, a 2:1 mixtureofN′-[2-butyl-1-(4-chlorobutyl)-1H-imidazo[4,5-c]quinolin-4-yl]-N,N-dimethylimidoformamideand 2-butyl-1-(4-chlorobutyl)-1H-imidazo[4,5-c]quinolin-4-amine (6.17g), a 4 M solution of hydrochloric acid in dioxane (21.15 mL, 84.56mmol), and methanol (200 mL) to provide a light orange solution. Thereaction was judged to be complete after stirring at ambient temperaturefor 43 hours. The volatiles were removed under reduced pressure and theresulting light yellow solid was partitioned between chloroform andsaturated aqueous sodium bicarbonate. The layers were separated and theaqueous layer was extracted with chloroform (1×). The organic layerswere combined, dried over anhydrous sodium sulfate, filtered and thenconcentrated under reduced pressure to afford2-butyl-1-(4-chlorobutyl)-1H-imidazo[4,5-c]quinolin-4-amine (4.65 g,14.05 mmol) as an off-white solid. The material was used without furtherpurification. MS (CI) for C₁₈H₂₃CIN₄ m/z 331 (MH⁺), 295.

Part B

A round bottom flask was charged with a magnetic stir bar,2-butyl-1-(4-chlorobutyl)-1H-imidazo[4,5-c]quinolin-4-amine (1.5 g, 4.53mmol), sodium thiomethoxide (0.48 g, 6.80 mmol), and anhydrous dimethylformamide (18 mL) under a nitrogen atmosphere. The reaction mixture washeated to 60° C. to give a homogeneous solution that was maintained at60° C. for 16 hours at which time the starting material was completelyconsumed. The solution was cooled and then partitioned betweenchloroform and water. The layers were separated and the organic layerwas washed with saturated aqueous sodium bicarbonate. The combinedaqueous layers were extracted with chloroform (1×). The combined organiclayers were washed with brine, dried over anhydrous sodium sulfate,filtered and then concentrated under reduced pressure to afford a darkbrown oil. The material was purified by chromatography over silica gel(90/10 dichloromethane/methanol) to provide a light yellow solid. Thesolid was recrystallized from dimethyl formamide and water to give2-butyl-1-[4-(methylthio)butyl]-1H-imidazo[4,5-c]quinolin-4-amine (0.83g, 2.42 mmol) as light yellow needles, m.p. 127–130° C.

Analysis. Calculated for C₁₉H₂₆N₄S: % C 66.63; % H, 7.65; % N, 16.36.Found % C 66.68; % H, 7.53; % N, 16.35.

¹H-NMR (500 MHz, DMSO) δ 8.04 (d, J==8.3 Hz, 1H), δ 7.61 (d, J=8.3 Hz,1H), δ 7.41 (t, J=8.3 Hz, 1H), δ 7.25 (t, J=8.3 Hz, 1H), δ 6.43 (bs,2H), δ 4.52 (t, J=7.6 Hz, 2H), δ 2.92 (t, J=7.8 Hz, 2H), δ 2.53 (t,J=7.3 Hz, 2H), δ 2.01 (s, 3H), δ 1.90 (m, 2H), δ 1.80 (p, J=7.8 Hz, 2H)δ 1.71 (p, J=7.3 Hz, 2H) δ 1.46 (sextet, J=7.3 Hz, 2H), δ 0.96 (t, J=7.3Hz, 3H)

MS (CI) for C₁₉H₂₆N₄S m/z 343 (MH⁺), 295, 241

EXAMPLE 52-butyl-1-[4-(methylsulfonyl)butyl]-1H-imidazo[4,5-c]quinolin-4-amine

Part A

A round bottom flask was charged with a magnetic stir bar,2-butyl-1-[4-(methylthio)butyl]-1H-imidazo[4,5-c]quinolin-4-amine (1.2g, 3.50 mmol), and chloroform (18 mL). Solid 3-chloroperbenzoic acid(1.72 g 7.71 mmol) was added to the resulting solution portion wise over15 minutes. The reaction was judged to be complete after stirring atambient temperature for 5 minutes. The solution was partitioned betweenchloroform and 1% aqueous sodium carbonate. The layers were separatedand the organic layer was washed with brine, dried over anhydrous sodiumsulfate, filtered and then concentrated under reduced pressure to afforda light brown solid. The material was purified by chromatography oversilica gel (90/10 dichloromethane/methanol to provide an off-whitesolid. The solid was recrystallized from acetonitrile and water to give2-butyl-1-[4-(methylsulfonyl)butyl]-1H-imidazo[4,5-c]quinolin-4-amine(0.61 g, 1.63 mmol) as off-white needles, m.p. 164–165° C.

Analysis. Calculated for C₁₉H₂₆N₄O₂S: % C 60.94; % H, 7.00; % N 14.96.Found % C 60.71; % H, 6.94; % N, 14.94.

¹H-NMR (300 MHz, DMSO) δ 8.03 (d, J=8.3 Hz, 1H) δ 7.61 (d, J=8.3 Hz,1H), δ 7.42 (t, J=8.3 Hz, 1H), 87.26 (t, J=8.3 Hz, 1H), δ 6.46 (s, 2H),δ 4.56 (t, J=7.6 Hz, 2H), δ 3.21 (t, J=7.3 Hz 2H), δ 2.96 (s, 3H), δ2.93 (t, J=7.8 Hz, 2H), δ 1.91 (m, 4H), δ 1.81 (p, J=7.3 Hz, 2H), δ 1.45(sextet, J=7.3 Hz, 2H), δ 0.96 (t, J=37.3 Hz, 3H)

MS (CI) for C₁₉H₂₆N₄S m/z 375 (MH⁺), 295

EXAMPLE 6 1-[2-(phenylthio)ethyl]-1H-imidazo[4,5-c]quinolin-4-amine

Part A

A round bottom flask was charged with a magnetic stir bar,2-(4-amino-1H-imidazo[4,5-c]quinolin-1-yl)ethanol (8.46 g, 37.06 mmol),and thionyl chloride (68.99 g, 57.99 mmol) under a nitrogen atmosphere.The reaction mixture was heated to 80° C. to give a heterogeneousreaction mixture that was maintained at 80° C. for 2 hours at which timethe starting material was completely consumed. The solution was cooledand quenched by the addition of water (400 mL). To the stirred solutionwas added solid sodium carbonate until the pH reached 10 at which time asolid precipitated out of solution. The solid was collected byfiltration to afford 1-(2-chloroethyl)-1H-imidazo[4,5-c]quinolin-4-amine(7.86 g, 31.86 mmol) as an off-white solid. The material was usedwithout further purification.

Part B

A round bottom flask was charged with a magnetic stir bar,1-(2-chloroethyl)-1H-imidazo[4,5-c]quinolin-4-amine (2.0 g, 8.11 mmol),sodium benzenethiolate (1.79 g, 12.16 mmol) and anhydrous dimethylsulfoxide (40 mL) under a nitrogen atmosphere. The reaction mixture washeated to 100° C. to give a homogeneous solution that was maintained at100° C. for 30 minutes at which time the starting material wascompletely consumed. The hot solution was poured into rapidly stirredwater (300 mL) which caused a solid to precipitate out of solution. Thesolid was collected by filtration to afford an off-white solid. Thematerial was triturated with acetonitrile and collected by filtration togive 1-[2-(phenylthio)ethyl]-1H-imidazo[4,5-c]quinolin-4-amine (2.08 g,6.49 mmol) as an off-white powder, m.p.233–235° C.

Analysis. Calculated for C₁₈H₁₆N₄S: % C 67.47; % H, 5.03; % N, 17.49.Found: % C 67.20; % H, 4.95; % N, 17.52.

¹H-NMR (300 MHz, DMSO) δ 8.14 (s, 1H), δ 7.76 (d, J=8.3 Hz, 1H), δ 7.60(t, J=8.3 Hz, 1H), δ 7.28–7.44 (m, 6H), δ 7.12 (t, J=8.3 Hz, 1H), δ 6.58(bs, 2H), δ 4.79 (t, J=6.8 Hz, 2H), 3.48 (t, 6.8 Hz, 2H).

MS (CI) for C₁₈H₁₆N₄S m/z 321 (MH⁺), 185, 137

EXAMPLE 7 1-[4-(phenylsulfonyl)butyl]-1H-imidazo[4,5-c]quinolin-4-amine

Part A

A round bottom flask was charged with a magnetic stir bar,N,N-dibenzyl-1H-imidazo[4,5-c]quinolin-4-amine (20.0 g, 55.04 mmol),sodium hydride (3.3 g, 60% dispersion, 82.56 mmol), and anhydrousdimethyl formamide (275 mL) under a nitrogen atmosphere. After thereaction mixture had stirred at ambient temperature for 2 hours,4-chloro-1-iodobutane (19.23 g, 88.06 mmol) was added and the resultinghomogeneous solution was stirred at ambient temperature for 48 hours atwhich time the starting material was consumed. The solution waspartitioned between ethyl acetate and water. The layers were separatedand the organic layer was washed with saturated aqueous sodiumbicarbonate and brine, dried over anhydrous sodium sulfate, filtered andthen concentrated under reduced pressure to afford a light yellow solid.The material was recrystallized from ethyl acetate and hexanes to giveN,N-benzyl-1-(4-chlorobutyl)-1H-imidazo[4,5-c]quinolin-4-amine (20.7 g,45.49 mmol) as white needles. MS (CI) for C₂₈H₂₇CIN₄ m/z 455 (MH⁺), 365,329, 239

Part B

A round bottom flask was charged with a magnetic stir bar,N,N-dibenzyl-1-(4-chlorobutyl)-1H-imidazo[4,5-c]quinolin-4-amine (7.0 g,15.38 mmol), sodium benzenethiolate (3.46 g, 26.15 mmol), and anhydrousdimethyl formamide (77 mL) under a nitrogen atmosphere. The reactionmixture was heated to 60° C. to give a heterogeneous mixture that wasmaintained at 60° C. for 4 hours at which time the starting material wascompletely consumed. The cooled solution was partitioned between ethylacetate and water. The layers were separated. The organic layer waswashed with saturated aqueous sodium bicarbonate and brine, dried overanhydrous sodium sulfate, filtered and then concentrated under reducedpressure to afford a colorless oil. The material was purified bychromatography over silica gel (80/20 hexanes/ethyl acetate) to provideN,N-dibenzyl-1-[4-(phenylthio)butyl]-1H-imidazo[4,5-c]quinolin-4-amine(7.5 g, 14.19 mmol) as a colorless oil. MS (CI) for C₃₄H₃₂N₄S m/z 529(MH⁺), 439, 349

Part C

A round bottom flask was charged with a magnetic stir bar,N,N-dibenzyl-1-[4-(phenylthio)butyl]-1H-imidazo[4,5-c]quinolin-4-amine(3.64 g, 6.88 mmol) and chloroform (34 mL). Solid 3-chloroperbenzoicacid (3.39 g, 15.14 mmol) was added portion wise to the resultingsolution over 5 minutes. The reaction was judged to be complete afterstirring at ambient temperature for 5 minutes. The solution waspartitioned between chloroform and 1% aqueous sodium carbonate. Thelayers were separated. The organic layer was washed with brine, driedover anhydrous sodium sulfate, filtered and then concentrated underreduced pressure to afford a red gum. The material was purified bychromatography over silica gel (dichloromethane) to provideN,N-dibenzyl-1-[4-(phenylsulfonyl)butyl]-1H-imidazo[4,5-c]quinolin-4-amine(2.85 g, 5.08 mmol) as a light pink gum. MS (CI) for C₃₄H₃₂N₄O₂S m/z 561(MH⁺), 471, 381

Part D

A round bottom flask was charged with a magnetic stir bar,N,N-dibenzyl-1-[4-(phenylsulfonyl)butyl]-1H-imidazo[4,5-c]quinolin-4-amine(1.0 g, 1.78 mmol), triflic acid (2.68 g, 17.83 mmol), and anhydrousdichloromethane (14 mL) under a nitrogen atmosphere. The reaction wasjudged to be complete after stirring at ambient temperature for 24hours. The solution was partitioned between chloroform and excessaqueous sodium hydroxide (20%). The layers were separated. The aqueouslayer was extracted with chloroform (3×). The organic layers werecombined and then concentrated under reduced pressure to afford a lightbrown solid. The material was purified by chromatography over silica gel(90/10 dichloromethane/methanol) to provide a fine white powder whichwas recrystallized from acetonitrile to give1-[4-(phenylsulfonyl)butyl]-1H-imidazo[4,5-c]quinolin-4-amine (0.32 g,0.84 mmol) as white needles, m.p. 175–177° C.

Analysis. Calculated for C₂₀H₂₀N₄O₂S: % C 63.14; % H, 5.30; % N, 14.73.Found: % C 63.14; % H, 5.24; % N, 14.77.

¹H-NMR (300 MHz, DMSO) δ 8.15 (s, 1H), δ 8.01 (d, J=8.3 Hz, 1H), δ 7.80(m, 2H), δ 7.71 (m, 1H), δ 7.60 (m, 3H), δ 7.44 (t, J=8.3 Hz, 1H), δ7.24 (t, J=8.3 Hz, 1H), δ 6.59 (bs, 2H), δ 4.59 (t, J=6.8 Hz, 2H), δ3.38 (t, J=7.8 Hz, 2H), δ 1.93 (m, 2H), δ 1.58 (m, 2H)

MS (CI) for C₂₀H₂₀N₄O₂S m/z 381 (MH⁺), 239

EXAMPLE 8 1-[4-(methylsulfonyl)butyl]-1H-imidazo[4,5-c]quinolin-4-amine

Part A

Using the general method of Example 7 Part B,N,N-dibenzyl-1-(4-chlorobutyl)-1H-imidazo[4,5-c]quinolin-4-amine (5.0 g,10.99 mmol) was converted toN,N-dibenzyl-1-[4-(methylthio)butyl]-1H-imidazo[4,5-c]quinolin-4-amineusing sodium thiomethoxide (1.16 g, 16.48 mmol). The material waspurified by chromatography over silica gel (80/20 hexanes/ethyl acetate)to provide the product (4.91 g, 10.52 mmol) as a colorless oil. MS (CI)for C₂₉H₃₀N₄S m/z 467 (MH⁺), 377, 287, 185

Part B

Using the general method of Example 7 Part C,N,N-dibenzyl-1-[4-(methylthio)butyl]-1H-imidazo[4,5-c]quinolin-4-amine(4.91 g, 15.52 mmol) was oxidized toN,N-dibenzyl-1-[4-(methylsulfonyl)butyl]-1H-imidazo[4,5-c]quinolin-4-aminewhich was purified by chromatography over silica gel (80/20hexanes/ethyl acetate) to provide the product (4.53 g, 9.08 mmol) as alight orange solid. MS (CI) for C₂₉H₃₀N₄O₂S m/z 499 (MH⁺), 409, 319

Part C

Using the general method of Example 7 Part D,N,N,-dibenzyl-1-[4-(methylsulfonyl)butyl]-1H-imidazo[4,5-c]quinolin-4-amine(4.53 g, 9.08 mmol) was converted to1-[4-(methylsulfonyl)butyl]-1H-imidazo[4,5-c]quinolin-4-amine. Thematerial was recrystallized from methanol and water to afford the titlecompound (1.33 g, 4.18 mmol) as white needles, m.p. 203–204° C.

Analysis. Calculated for C₁₅H₁₈N₄O₂S: % C 56.58; % H, 5.70; % N, 17.60.Found: % C 56.33; % H, 5.63; % N, 17.41.

¹H-NMR (300 MHz, DMSO) δ 8.22 (s, 1H), δ 8.06 (d, J=8.3 Hz, 1H), δ 7.62(d, J=8.3 Hz, 1H), δ 7.45 (t, J=8.3 Hz, 1H), δ 7.27 (t, J=8.3 Hz, 1H), δ6.59 (bs, 2H), δ 4.65 (t, J=6.8 Hz, 2H), δ 3.19 (t, J=7.8 Hz, 2H), δ2.93 (s, 3H), δ 1.99 (m, 2H), δ 1.74 (m, 2H)

MS (CI) for C₁₅H₁₈N₄O₂S m/z 319 (MH⁺), 239

EXAMPLE 9 1-[4-(phenylthio)butyl]-1H-imidazo[4,5-c]quinolin-4-amine

Part A

Using the general method of Example 1 Part D,N-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)quinoline-3,4-diamine (101.21g, 292.90 mmol) was cyclized to1-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)-1H-imidazo[4,5-c]quinolineusing triethyl orthoformate (65.11 g, 439.35 mmol). The product (75.0 g,210.93 mmol) was isolated as a brown oil and used without furtherpurification.

Part B

Using the general method of Example 1 Part E,1-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)-1H-imidazo[4,5-c]quinoline(42.2 g, 118.69 mmol) was oxidized to1-(4-{([tert-butyl(dimethyl)silyl]oxy}butyl)-1H-imidazo[4,5-c]quinoline-5N-oxide(44.10 g, 118.69 mmol) which was isolated without further purificationas a tan solid.

Part C

Using the general method of Example 3 Part B,1-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)-1H-imidazo[4,5-c]quinoline-5N-oxide(44.10 g, 118.69 mmol) was aminated to provide1-(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)-1H-imidazo[4,5-c]quinolin-4-amine.The material was triturated with ethyl ether and collected by filtrationto afford the product (21.54 g, 58.12 mmol) as a light brown solid whichwas used without further purification.

Part D

Using the general method of Example 3 Part C,1(4-{[tert-butyl(dimethyl)silyl]oxy}butyl)-1H-imidazo[4,5-c]quinolin-4-amine(21.5 g, 58.02 mmol) was converted to4-(4-amino-1H-imidazo[4,5-c]quinolin-1-yl butan-1-ol. The material wastriturated with cold methanol (0° C.) and collected by filtration toafford the product (13.92 g, 54.30 mmol) which was used without furtherpurification. MS (CI) for C₁₄H₁₆N₄O m/z 257 (MH^(+l ),) 185

Part E

Using the general method of Example 6 Part A,4-(4-amino-1H-imidazo[4,5-c]quinolin-1-yl)butan-1-ol (5.0 g, 19.51 mmol)was chlorinated to provide1-(4-chlorobutyl)-1H-imidazo[4,5-c]quinolin-4-amine (4.92 g, 17.91 mmol)which was isolated without further purification as an off-white solid.

Part F

Using the general method of Example 6 Part B, except that the reactiontemperature was lowered to 80° C.,1-(4-chlorobutyl)-1H-imidazo[4,5-c]quinolin-4-amine (1.5 g, 5.46 mmol)was converted to1-[4-(phenylthio)butyl]-1H-imidazo[4,5-c]quinolin-4-amine. The resultingsolid (1.53 g) was dissolved in acetonitrile (90 mL) and brought toreflux. Activated charcoal (0.9 g) was added and the resulting mixturewas heated at reflux for 5 minutes and then the charcoal was removed byfiltration through fluted paper to provide a colorless solution. Thetitle compound (0.86 g, 2.47 mmol) was isolated as white needles, m.p158–160° C.

Analysis. Calculated for C₂₀H₂₀N₄S: % C 68.94; % H, 5.79; % N, 16.08.Found: % C 68.70; % H, 5.74; % N, 16.08.

¹H-NMR (300 MHz, DMSO) δ 8.18 (s, 1H), δ 8.05 (d, J=8.3 Hz, 1H), δ 7.63(d, J=8.3 Hz, 1H), δ 7.45 (t, J=8.3 Hz, 1H), δ 7.26 (m, 5H), δ 7.14–7.19(m, 1H), δ (bs, 2H), δ 4.62 (t, J=6.8 Hz, 2H), δ 3.00 (t, J=7.3 Hz, 2H),δ 2.00 (m, 2H), δ 1.61 (m, 2H)

MS (CI) for C₂₀H₂₀N₄S m/z 349 (MH⁺), 185

EXAMPLE 10 1-[4-(methylthio)butyl]-1H-imidazo[4,5-c]quinolin-4-amine

Part A

Using the general method of Example 6 Part B, except that the reactiontemperatures was lowered to 80° C.,1-(4-chlorobutyl)-1H-imidazo[4,5-c]quinolin-4-amine (1.5 g, 5.46 mmol)was converted to1-[4-(methylthio)butyl]-1H-imidazo[4,5-c]quinolin-4-amine using sodiumthiomethoxide (0.88 g, 12.56 mmol) in lieu of sodium benzenethiolate.The resulting solid (1.26 g) was dissolved in acetonitrile (40 mL) andbrought to reflux. Activated charcoal (0.7 g) was added, the resultingmixture was heated at reflux for 5 minutes and then the charcoal wasremoved by filtration through fluted paper to provide a colorlesssolution. The solution was concentrated under reduced pressure to give asolid that was recrystallized from acetonitrile. The title compound(0.66 g, 2.30 mmol) was isolated as white needles, m.p 163–164° C.

Analysis. Calculated for C₁₅H₁₈N₄S: % C 62.91; % H, 6.34; % N, 19.56.Found: % C 62.70; % H, 6.19; % N, 19.45.

¹H-NMR (300 MHz, DMSO) δ 8.21 (s, 1H), δ 8.06 (d, J=8.3 Hz, 1H), δ 7.62(d, J=8.3 Hz, 1H), δ 7.44 (t, J=8.3 Hz, 1H), δ 7.26 (t, J=8.3 Hz, 1H), δ6.59 (bs, 2H), δ 4.62 (t, J=7.6 Hz, 2H), δ 2.50 (t, J=6.8 Hz, 2H), δ1.99 (s, 3H), δ 1.95 (p, J=7.3 Hz, 2H), δ 1.59 (p, J=73 Hz, 2H)

MS (CI) for C₁₅H₁₈N₄S m/z 287 (MH⁻), 185

EXAMPLE 112-butyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4.5-c]quinolin-4-amine

Part A

Using the general method of Example 1 Part A, 4-chloro-3-nitroquinoline(107.7 g, 525.87 mmol) was converted to 5-[(3nitroqunolin-4-yl)amino]pentan-1-ol using 5-amino-1-pentanol (79.82 g,788.81 mmol) in lieu of 4-amino-butanol. The product (117.22 g, 425.77mmol) was used without further purification as a dark yellow solid. MS(CI) for C₁₄H₁₇N₃O₃ m/z 276 (MH⁺), 224

Part B

A round bottom flask was charged with a magnetic stir bar,5-[(3-nitroquinolin-4-yl)amino]pentan-1-ol (5.0 g, 18.16 mmol), andthionyl chloride (40.78 g, 0.34 mmol) under a nitrogen atmospheres Thereaction mixture was heated to 80° C. to give a homogeneous solutionthat was maintained at 80° C. for 1 hour at which time the startingmaterial was completely consumed. The volatiles were removed underreduced pressure and the resulting oil stirred in water made basic (pH10) with solid sodium carbonate. The resulting solid was collected byfiltration to afford N-(5-chloropentyl)-3-nitroquinolin-4-amine (4.80 g,16.34 mmol) which was used without further purification.

Part C

Using the general method of Example 6 Part B, except that the reactiontemperature was lowered to 80° C.,N-(5-chloropentyl)-3-nitroquinolin-4-amine (4.75 g, 16.17 mmol) wasconverted to N-[5-(methylthio)pentyl]-3-nitroquinolin-4-amine usingsodium thiomethoxide (1.43 g, 19.40 mmol) in lieu of sodiumbenzenethiolate. The product (3.28 g, 10.74 mmol) was isolated withoutfurther purification as a light yellow solid. MS (CI) for C₁₅H₁₉N₃O₂Sm/z 306 (MH⁺), 272, 117

Part D

Using the general method of Example 1 Part C,N-[5-(methylthio)pentyl]-3-nitroquinolin-4-amine (3.20 g, 10.48 mmol)was reduced to N⁴-[5-(methylthio)pentyl]quinoline-3,4-diamine (2.89 g,10.48 mmol) which was isolated without further purification as a brownoil.

Part E

Using the general method of Example 1 Part D,N⁴-[5-(methylthio)pentyl]quinoline-3,4-diamine (2.89 g, 10.48 mmol) wascyclized to provide2-butyl-1-[5-methylthio)pentyl]-1H-imidazo[4,5-c]quinoline. The materialwas purified by chromatography over silica gel (ethyl acetate) to affordthe product (2.10 g, 6.15 mmol) as a light brown oil.

Part F

A round bottom flask was charged with a magnetic stir bar,2-butyl-1-[5-(methylthio)pentyl]-1H-imidazo[4,5-c]quinoline (2.1 g, 6.15mmol) and chloroform (31 mL). Solid 3-chloroperbenzoic acid (4.41 g,19.68 mmol) was added portion wise to the solution over 10 minutes andthe reaction was stirred at ambient temperature for 30 minutes at whichtime the starting material was completely consumed. The solution waspartitioned between chloroform and saturated aqueous sodium bicarbonate.The layers were separated. The organic layer was washed with saturatedaqueous sodium bicarbonate and brine, dried over anhydrous sodiumsulfate, filtered and then concentrated under reduced pressure to afford2-butyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinoline-5N-oxide(2.40 g, 6.15 mmol) as a tan solid. The material was used withoutfurther purification.

Part G

Using the general method of Example 3 Part B,2-butyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinoline-5N-oxide(2.40 g, 6.15 mmol) was aminated to provide2-butyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinolin-4-amine.The resulting solid (2.24 g) was dissolved in acetonitrile (40 mL) andbrought to reflux. Activated charcoal (1 g) was added and the resultingmixture was heated at reflux for 5 minutes and then the charcoal wasremoved by filtration through fluted paper to provide a light brownsolution. Upon cooling2-butyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinolin-4-amine(0.90 g, 2.32 mmol) was isolated as white needles, m.p. 173–175° C.

Analysis. Calculated for C₂₀H₂₈N₄O₂S: % C 61.83; % H, 7.26; % N, 14.42.Found: % C 61.58; % H, 7.27; % N, 14.36.

¹H-NMR (300 MHz, DMSO) δ 8.01 (d, J=8.3 Hz, 1H), 7.61 (d, J=8.3 Hz, 1H),δ 7.41 (t, J=8.3 Hz, 1H), δ 7.26 (t, J=8.3 Hz, 1H), δ 6.45 (bs, 2H), δ4.51 (t, J=7.6 Hz, 2H), δ 3.10 (t, J=7.8 Hz, 2H), δ 2.92 (s, 3H), δ 2.92(t, J=7.3 Hz, 2H), δ 1.76 (m, 6H), δ 1.54 (m, 2H), δ 1.46 (sextet, J=7.3Hz, 2H), δ 0.99 (t, J=7.3 Hz, 3H)

MS (CI) for C₂₀H₂₈N₄O₂S m/z 389 (MH⁺)

EXAMPLE 122-methyl-1-[5-(methylsulfonyl)pentyl]-1-H-imidazo[4,5-c]quinolin-4-amine

Part A

Using the general method of Example 1 Part D,N⁴-[5-(methylthio)pentyl]quinoline-3,4-diamine (4.53 g, 16.37 mmol) wascyclized to provide2-methyl-1-[5-(methylthio)pentyl)-1H-imidazo[4,5-c]quinoline using1,1,1-trimethoxyethane (2.95 g, 24.6 mmol) and pyridine hydrochloride(0.1 g). The material was triturated with ethyl ether and collected byfiltration to afford the product (3.78 g, 12.62 mmol) as a light brownsolid which was used without further purification.

Part B

Using the general method of Example 11 Part F,2-methyl-1-[5-(methylthio)pentyl]-1H-imidazo[4,5-c]quinoline (3.78 g,12.62 mmol) was oxidized to2-methyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinoline-5N-oxide(4.38 g, 12.62 mmol) which was isolated as a tan solid and used withoutpurification.

Part C

Using the general method of Example 3 Part B,2-methyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinoline-5N-oxide(4.38 g, 12.62 mmol) was aminated to provide2-methyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinolin-4-amine.The resulting solid was triturated with acetonitrile and collected byfiltration to afford the title compound (0.8 g, 2.31 mmol) as anoff-white solid, m.p. 235–240° C.

Analysis. Calculated for C₁₇H₂₂N₄O₂S: % C 58.94; % H, 6.40; % N, 16.17.Found: % C 58.77; % H, 6.34; % N, 16.39.

¹H-NMR (300 MHz, DMSO) δ 8.02 (d, J=8.3 Hz, 1H), δ 7.60 (d, J=8.3 Hz,1H), δ 7.41 (t, J=8.3 Hz, 1H), δ 7.25 (t, J=8.3 Hz, 1H), δ 6.49 (bs,2H), δ 4.50 (t, J=7.3 Hz, 2H), δ 3.12 (t, J=7.8 Hz, 2H), δ 2.92 (s, 3H),δ 2.61 (s, 3H), δ 1.86 (m, 2H), δ 1.74 (m, 2H), δ 1.53 (m, 2H)

MS (CI) for C₁₇H₂₂N₄O₂S m/z 347 (MH⁺), 267

EXAMPLE 13

2-ethyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinolin-4-amine

Part A

Using the general method of Example 1 Part D,N⁴-(5-(methylthio)pentyl]quinoline-3,4-diamine (4.53 g, 16.37 mmol) wascyclized to 2-ethyl-1-[5-(methylthio)pentyl]-1H-imidazo[4,5-c]quinolineusing triethyl orthopropionate (4.3 g, 24.56 mmol) and pyridinehydrochloride (0.1 g). The material was triturated with ethyl ether andcollected by filtration to afford the product (3.25 g, 10.37 mmol) as anoff-white powder which was used without further purification.

Part B

Using the general method of Example 11 Part F,2-ethyl-1-[5-(methylthio)pentyl]-1H-imidazo[4,5-c]quinoline (3.25 g,10.37 mmol) was oxidized to2-ethyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinoline-5N-oxide(3.75 g, 10.37 mmol) which was isolated as a tan solid and used withoutpurification.

Part C

Using the general method of Example 3 Part B,2-ethyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinoline-5N-oxide(3.75 g 10.37 mmol) was aminated to provide2-ethyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinolin-4-amine.The resulting solid was recrystallized sequentially from ethanol andacetonitrile to afford the title compound (1.4 g, 3.88 mmol) as offwhite needles, m.p.189–191° C.

Analysis. Calculated for C₁₈H₂₄N₄O₂S: % C 59.98; % H, 6.71; % N, 15.54.Found: % C 59.71; % H, 6.68; % N, 15.64.

¹H-NMR (300 MHz, DMSO) δ 8.01 (d, J=8.3 Hz, 1H), δ 7.61 (d, J=8.3 Hz,1H), δ 7.42 (t, J=8.3 Hz, 1H), δ 7.26(t, J=8.3 Hz, 1H), δ 6.45(bs, 2H),δ 4.50 (t, J=7.6 Hz, 2H), δ 3.10 (t, J=7.8 Hz, 2H), δ 2.95 (q, J=7.3 Hz,2H), δ 2.92 (s, 3H), δ 1.85 (m, 2H), δ 1.74 (m, 2H), δ 1.55 (m, 2H), δ1.38 (t, J=7.3 Hz, 3H)

MS (CI) for C₁₈H₂₄N₄O₂S m/z 361 (MH⁺), 281

EXAMPLE 141-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinolin-4-amine

Part A

Using the general method of Example 1 Part D,N⁴-[5-(methylthio)pentyl]quinoline-3,4-diamine (4.53 g, 16.37 mmol) wascyclized to 1-[5-(methylthio)pentyl]-1H-imidazo[4,5-c]quinoline usingtriethyl orthoformate (3.64 g, 24.56 mmol) and pyridine hydrochloride(0.1 g). The product (4.05 g, 14.19 mmol) was isolated as a brown oiland used without further purification.

Part B

Using the general method of Example 11 Part F,1-[5-(methylthio)pentyl]-1H-imidazo[4,5-c]quinoline (4.05 g, 14.19 mmol)was oxidized to1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinoline-5N-oxide (4.73g, 14.19 mmol) which was isolated as a tan solid and used withoutfurther purification.

Part C

Using the general method of Example 3 Part B,1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinoline-5N-oxide (4.19aminated to provide1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinolin-4-amine. Thematerial was purified by chromatography over silica gel (95/5dichloromethane/methanol) to afford a light yellow solid. The solid wasrecrystallized from dimethyl formamide to give the title compound (0.43g, 1.29 mmol) as a light yellow, granular solid, m.p. 199–201° C.

Analysis. Calculated for C₁₆H₂₀N₄O₂S: % C 57.81; % H, 6.06; % N, 16.85.Found: % C 57.01; % H, 6.06; % N, 16.70.

¹H-NMR (300 MHz, DMSO) δ 8.20 (S, 1H), δ 8.04 (d, J=8.3 Hz, 1H), δ 7.62(d, J=8.3 Hz, 1H), δ 7.44 (t, J=8.3 Hz, 1H), δ 7.27 (t, J=8.3 Hz, 1H), δ6.57 (bs, 2H), δ 4.61 (t, J=6.8 Hz, 2H), δ 3.09 (t, J=7.8 Hz, 2H), δ2.92 (s, 3H), δ 1.91 (p, J=7.6 Hz, 2H), δ 1.73 (m, 2H), δ 1.45 (m, 2H)

MS (CI) for C₁₆H₂₀N₄O₂S m/z 333 (MH⁺)

EXAMPLE 152-hexyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinolin-4-amine

Part A

A round bottom flask was charged with a magnetic stir bar,N⁴-[5-(methylthio)pentyl]quinoline-3,4-diamine (3.17 g, 11.46 mmol) andanhydrous pyridine (46 mL) under a nitrogen atmosphere. The resultinghomogeneous solution was cooled to 0° C. in an ice-water bath. To thecooled solution was added neat heptanoyl chloride (1.87 g, 12.61 mmol).The reaction was judged to be complete after stirring at ambienttemperature for 1 hour. The volatiles were removed under reducedpressure and the resulting oil was partitioned between chloroform andwater. The layers were separated. The organic layer was washed withsaturated aqueous sodium bicarbonate and brine, dried over anhydroussodium sulfate, filtered and then concentrated under reduced pressure toafford N-(4-[{5-(methylthio)pentyl]amino}quinolin-3-yl)heptanamide (4.44g, 11.46 mmol) which was isolated as a brown oil and used withoutfurther purification.

Part B

A round bottom flask was charged with a magnetic stir bar,N-(4-{[5-(methylthio)pentyl]amino}quinolin-3-yl)heptanamide (4.44 g,11.46 mmol), pyridine hydrochloride (0.13 g, 1.15 mmol), and anhydrouspyridine (50 mL) under a nitrogen atmosphere. The reaction was judged tobe complete after stirring at reflux for 1.5 hours. The solution wascooled and partitioned between ethyl acetate and water. The layers wereseparated. The organic layer was washed with saturated aqueous sodiumbicarbonate and brine, dried over anhydrous sodium sulfate, filtered andthen concentrated under reduced pressure to afford2-hexyl-1-[5-(methylthio)pentyl]-1H-imidazo[4,5-c]quinoline (4.0 g,10.82 mmol) as a brown oil which was used without further purification.

Part C

Using the general method of Example 11 Part F,2-hexyl-1-[5-(methylthio)pentyl]-1H-imidazo[4,5-c]quinoline (4.0 g,10.82 mmol) was oxidized to2-hexyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinoline-5N-oxide(4.52 g, 10.82 mmol) which was isolated as a tan solid and used withoutfurther purification.

Part D

Using the general method of Example 3 Part B2-hexyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinoline-5N-oxide(4.0 g, 10.82 mmol) was aminated to provide2-hexyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinolin-4-amine.The material was recrystallized from acetonitrile to afford the titlecompound (2.25 g, 5.40 mmol) as off-white needles, m.p. 168–171° C.

Analysis: Calculated for C₂₂H₃₂N₄O₂S: % C 63.43; % H, 7.74; % N, 13.45.Found: % C 63.06; % H, 7.66; % N, 13.81.

¹H-NMR (300 MHz, DMSO) δ 8.01 (d, J=8.3 Hz, 1H), δ 7.62 (d, J=8.3 Hz,1H), δ 7.42 (t, J=8.3 Hz, 1H), δ 7.26 (t, J=8.3 Hz, 1H), δ 6.51 (bs,2H), δ 4.51 (t, J=7.3 Hz, 2H), δ 3.10 (t, J=7.8 Hz, 2H), δ 2.93 (s, 3H),δ 2.93 (t, J=7.3 Hz, 2H), δ 1.71–1.87 (m, 6H), δ 1.54 (m, 2H), δ 1.44(m, 2H), δ 1.33 (m, 4H), δ 0.89 (t, J=7.3 Hz, 3H)

MS (CI) for C₂₂H₃₂N₄O₂S m/z 417 (MH⁺), 337

EXAMPLE 162-(2-methoxyethyl)-1-[5-methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinolin-4-amine

Part A

A round bottom flask was charged with a magnetic stir bar,N⁴-[5-(methylthio)pentyl]quinoline-3,4-diamine (3.56 g, 12.93 mmol) andanhydrous pyridine (52 mL) under a nitrogen atmosphere. The resultinghomogeneous solution was cooled to 0° C. in an ice-water bath. To thecooled solution was added neat 3-methoxypropionyl chloride (2.74 g,22.36 mmol). After addition of the acid chloride, the reaction washeated to reflux for 14 hours at which time the acylated intermediatewas completely consumed. The solution was cooled and then partitionedbetween chloroform and saturated aqueous ammonium chloride. The layerswere separated. The organic layer was washed with saturated aqueoussodium bicarbonate, dried over anhydrous sodium sulfate, filtered andthen concentrated under reduced pressure to afford2-(2-methoxyethyl)-1-[5-(methylthio)pentyl]-1H-imidazo[4,5-c]quinoline(3.0 g, 8.73 mmol) which was isolated as a brown oil and used withoutfurther purification.

Part B

Using the general method of Example 11 Part F,2-(2-methoxyethyl)-1-[5-(methylthio)pentyl]-1H-imidazo[4,5-c]quinoline(3.0 g, 8.73 mmol) was oxidized to2-(2-methoxyethyl)-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinoline-5N-oxide(3.41 g, 8.73 mmol) which was isolated as a tan solid and used withoutfurther purification.

Part C

Using the general method of Example 3 Part B,2-(2-methoxyethyl)-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinoline(3.0 g, 8.73 mmol) was aminated to provide2-(2-methoxyethyl)-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinolin-4-amine.The resulting solid was purified by chromatography over silica gel (95/5dichloromethane/methanol) to provide a gummy solid. The solid wasrecrystallized from acetonitrile to give the title compound (0.54 g,1.38 mmol) as an off-white powder, m.p. 158–160° C.

Analysis. Calculated for C₁₉H₂₆N₄O₃S: % C 58.44; % H, 6.71; % N, 14.35.Found: % C 58.24; % H, 6.76; % N, 14.70.

¹H-NMR (300 MHz, DMSO) δ 8.02 (d, J=8.3 Hz, 1H), δ 7.62 (d, J=8.3 Hz,1H), δ 7.42 (t, J=8.3. Hz, 1H), δ 7.26 (t, J=8.3 Hz, 1H), δ 6.50 (bs,2H), δ 4.53 (t, J=7.6 Hz, 2H), δ 3.83 (t, J=6.8 Hz, 2H), δ 3.30(s, 3H),δ 3.19(t, J=6.8 Hz, 2H),δ 3.11 (t, J=7.8 Hz, 2H), δ 2.93 (s, 3H), δ 1.85(m, 2H), δ 1.76 (m, 2H), δ 1.57 (m, 2H)

MS (CI) for C₁₉H₂₆N₄O₃S m/z 391 (MH⁺), 359

EXAMPLE 172-butyl-1-[5-(methylthio)pentyl]-1H-imidazo[4,5-c]quinolin-4-amine

Part A

Using the general method of Example 1 Part C,N-(5-chloropentyl)-3-nitroquinolin-4-amine (2.0 g, 6.80 mmol) wasreduced to provide N⁴-(5-chloropentyl)quinoline-3,4-diamine (1.79 g,6.80 mmol) which was isolated as a brown oil and used without furtherpurification.

Part B

Using the general method of Example 1 Part D,N⁴-(5-chloropentyl)quinoline-3,4-diamine (1.79 g, 6.80 mmol) wascyclized to 2-butyl-1-(5-chloropentyl)-1H-imidazo[4,5-c]quinoline usingtrimethyl orthovalerate (2.55 g, 15.72 mmol) and pyridine hydrochloride(0.079 g). The product (1.95 g, 5.91 mmol) was isolated as an off-whitesolid and used without further purification.

Part C

Using the general method of Example 1 Part E,2-butyl-1-(5-chloropentyl)-1H-imidazo[4,5-c]quinoline (1.95 g, 5.91mmol) was oxidized to2-butyl-1-(5-chloropentyl)-1H-imidazo[4,5-c]quinoline-5N-oxide (2.04 g,5.91 mmol) which was isolated as a tan solid and used without furtherpurification.

Part D

Using the general method of Example 3 Part B,2-butyl-1-(5-chloropentyl)-1H-imidazo[4,5-c]quinoline-5N-oxide (2.04 g,5.91 mmol) was aminated to provide2-butyl-1-(5-chloropentyl)-1H-imidazo[4,5-c]quinolin-4-amine. Theresulting solid was recrystallized from ethanol to afford the product(0.85 g, 2.46 mmol) as a fine white powder, m.p. 144–146° C.

Analysis. Calculated for C₁₉H₂₅CIN₄: % C 66.17; % H, 7.31; % N, 16.24.Found: % C 66.44; % H, 7.55; % N, 16.29.

MS (CI) for C₁₉H₂₅CIN₄ m/z 345 (MH⁺), 309

Part E

Using the general method of Example 6 Part B, except that the reactiontemperature was lowered to 80° C.,2-butyl-1-(5-chloropentyl)-1H-imidazo[4,5-c]quinolin-4-amine (2.0 g,5.80 mmol) was converted to2-butyl-1-[5-(methylthio)pentyl]-1H-imidazo[4,5-c]quinolin-4-amine usingsodium thiomethoxide (0.68 g, 8.70 mmol) in lieu of sodiumbenzenethiolate. The resulting solid was partitioned between chloroformand saturated aqueous sodium bicarbonate. The layers were separated. Theorganic layer was washed with brine, dried over anhydrous sodiumsulfate, filtered and then concentrated under reduced pressure to afforda white solid. The material was recrystallized from acetonitrile to givethe title compound (1.91 g, 5.36 mmol) as a fine white solid, m.p.112–114° C.

Analysis. Calculated for C₂₀H₂₈N₄S: % C 67.38; % H, 7.92; % N, 15.71.Found: % C 67.26; % H, 8.08; % N, 15.74.

¹H-NMR (300 MHz, DMSO) δ 8.01 (d, J=8.3 Hz, 1H), δ 7.61 (d, J=8.3 Hz,1H), δ 7.41 (t, J=8.3 Hz, H), δ 7.25 (t, J=8.3 Hz, 1H), δ 6.45 (bs, 2H),δ 4.50 (t, J=7.8 Hz, 2H), δ 2.92 (t, J=7.6 Hz, 2H), δ 2.46 (t, J=7.3 Hz,2H), δ 2.01 (s, 3H), δ 1.80 (m, 4H), δ 1.42–1.61 (m, 6H), δ 0.96 (t,J=7.3 Hz, 3H)

MS (CI) for C₂₀H₂₈N₄S m/z 357 (MH⁺), 309

EXAMPLE 182-butyl-1-[5-(methylsulfinyl)pentyl]-1H-imidazo[4,5-c]quinolin-4-amine

A round bottom flask was charged with a magnetic stir bar,2butyl-1-[5-(methylthio)pentyl]-1H-imidazo[4,5-c]quinolin-4-amine (1.0g, 2.80 mmol) and chloroform (14 mL). Solid 3-chloroperbenzoic acid(0.69 g, 3.09 mmol) was added portion wise over 5 minutes and thereaction was stirred at ambient temperature for 20 minutes at which timethe starting material was completely consumed. The solution waspartitioned between chloroform and saturated aqueous sodium bicarbonate.The layers were separated. The organic layer was washed with saturatedaqueous sodium bicarbonate and brine, dried over anhydrous sodiumsulfate filtered and then concentrated under reduced pressure to affordan off-white solid which was shown by ¹H-NMR to be the 3-chlorobenzoicacid salt of the desired product. The solid was stirred in water andthen made basic (pH 10) by addition of solid sodium carbonate. Theresulting free base was collected by filtration to provide a white solidwhich was recrystallized from acetonitrile to give2-butyl-1-[5-(methylsulfinyl)pentyl]-1H-imidazo[4,5-c]quinolin-4-amine(0.40 g, 1.07 mmol) as a white powder, m.p. 119–121° C.

Analysis. Calculated for C₂₀H₂₈N₄OS (H₂O)₁: % C 61.51; % H, 7.74; % N,14.35. Found: % C 61.64; % H, 7.82; % N, 14.32.

¹H-NMR (300 MHz, DMSO) δ 8.01 (d, J=8.3 Hz, 1H), δ 7.60 (d, J=8.3 Hz,1H), δ 7.41 (t, J=8.3 Hz, 1H), δ 7.26 (t, J=8.3 Hz, 1H), δ 6.44 (bs,2H), δ 4.51 (t, J=7.6 Hz, 2H), δ 2.92 (t, J=7.8 Hz, 2H), δ 2.57–2.74 (m,2H), δ 2.50 (s, 3H, δ 1.80 (m, 4H), δ 1,66 (m, 2H), δ 1.55 (m, 2H), δ1.48 (m, 2H), δ 0.96 (t, 37.3 Hz, 3H)

MS (CI) for C₂₀H₂₈N₄OS (H₂O)₁ m/z 373 (MH⁺), 309, 253

EXAMPLE 192-butyl-1-[3-(methylsulfonyl)propyl]-1H-imidazo[4,5-c]quinolin-4-amine

Part A

A round bottom flask was charged with a magnetic stir bar,3-[(3-nitroquinolin-4-yl)amino]propan-1-ol (20.75 g, 83.93 mmol),thionyl chloride (15.0 g, 125.89 mmol), and dichloromethane (420 mL).The bright yellow, homogeneous solution was stirred at ambienttemperature for 2 hours at which time the starting material wascompletely consumed. The volatiles were removed under reduced pressureand he resulting solid stirred in water (400 mL) made basic (pH 10) withsolid sodium carbonate. A bright yellow solid was collected byfiltration to afford N-(3-chloropropyl)-3-nitroquinolin-4-amine (21.63g, 81.41 mmol) which was used without further purification.

Part B

Using the general method of Example 1 Part C,N-(3-chloropropyl)-3-nitroquinolin-4-amine (10.0 g, 37.63 mmol) wasreduced to provide N⁴-(3-chloropropyl)quinoline-3,4-diamine (8.87 g,37.63 mmol) which was isolated as a brown oil and used without furtherpurification.

Part C

Using the general method of Example 1 Part D,N⁴-(3-chloropropyl)quinoline-3,4-diamine (8.87 g, 37.63 mmol) wascyclized to provide2-butyl-1-(3-chloropropyl)-1H-imidazo[4,5-c]quinoline using trimethylorthovalerate (7.33 g, 45.16 mmol) and pyridine hydrochloride (0.43 g).The resulting solid was triturated with ethyl ether and collected byfiltration to afford the product (9.00 g, 29.82 mmol) as an off-whitesolid. The material was used without further purification.

Part D

Using the general method of Example 1 Part E,2-butyl-1-(3-chloropropyl)-1H-imidazo[4,5-c]quinoline (9.0 g, 29.82mmol) was oxidized to2-butyl-1-(3-chloropropyl)-1H-imidazo[4,5-c]quinoline-5N-oxide (9.48 g,29.82 mmol) which was isolated as a tan solid and used withoutpurification.

Part E

Using the general-method of Example 3 Part B,2-butyl-1-(3-chloropropyl)-1H-imidazo[4,5-c]quinoline-5N-oxide (9.48 g,29.82 mmol) was aminated to provide2-butyl-1-(3-chloropropyl)-1H-imidazo[4,5-c]quinolin-4-amine. Theresulting solid was purified by chromatography over silica gel (95/5dichloromethane/methanol) to provide the product (6.4 g, 20.20 mmol) asa tan solid.

Part F

Using the general method of Example 6 Part B, except that the reactiontemperature was lowered to 80° C.,2-butyl-1-(3-chloropropyl)-1H-imidazo[4,5-c]quinolin-4-amine (2.0 g,6.31 mmol) was converted to2-butyl-1-[3-(methylthio)propyl]-1H-imidazo[4,5-c]quinolin-4-amine usingsodium thiomethoxide (0.74 g, 9.47 mmol) in lieu of sodiumbenzenethiolate. The resulting solid was partitioned between chloroformand saturated aqueous sodium bicarbonate. The layers were separated. Theorganic layer was washed with brine, dried over anhydrous sodiumsulfate, filtered and then concentrated under reduced pressure to affordthe title compound (2.0 g, 6.09 mmol) as a white solid. The material wasused without further purification.

Part G

Using the general method of Example 5 Part A,2-butyl-1-[3-(methylthio)propyl]-1H-imidazo[4,5-c]quinolin-4-amine (2.0g, 6.09 mmol) was oxidized to2-butyl-1-[3-(methylsulfonyl)propyl]-1H-imidazo[4,5-c]quinolin-4-amine.The resulting solid was triturated with methanol and collected byfiltration to afford the title compound (0.96 g, 2.66 mmol) as anoff-white powder, m.p. 233–236° C.

Analysis. Calculated for C₁₈H₂₄N₄O₂S: % C 59.98; % H, 6.71; % N, 15.54.Found: % C 59.71; % H, 6.65; % N, 15.43.

¹H-NMR (300 MHz, DMSO) , 8.10 (d, J=8.3 Hz, 1H), δ 7.61 (d, J=8.3 Hz,1H), δ 7.42 (t, J=8.3 Hz, 1H), δ 7.25 (t, J=8.3 Hz, 1H), δ 6.47 (bs,2H), δ 4.66 (t, J=7.8 Hz, 2H), δ 3.40 (t, J=7.3 Hz, 2H), δ 3.01 (s, 3H),δ 2.94 (t, J=7.8 Hz, 2H), δ 2.22 (m, 2H), δ 1.80 (m, 2H), δ 1.46(sextet, J=7.3 Hz, 2H), δ 0.96 (t, J=7.3 Hz, 3H)

MS (CI) for C₁₈H₂₄N₄O₂S m/z 361 (MH⁺), 281, 235

EXAMPLE 202-butyl-1-[3-(phenylsulfonyl)propyl]-1H-imidazo[4,5-c]quinolin-4-amine

Part A

A round bottom flask was charged with a magnetic stir bar, benzenethiol(0.68 g, 6.21 mmol), sodium hydride (0.25 g, 60% dispersion, 6.21 mmol),and anhydrous dimethyl formamide (28 mL) under a nitrogen atmosphere.After the reaction mixture had stirred at ambient temperature for 30minutes, 2-butyl-1-(3-chloropropyl)-1H-imidazo[4,5-c]quinolin-4-amine(1.64 g, 5.18 mmol) was added and the resulting cloudy solution washeated to 80° C. and maintained at 80° C. for 2.5 hours at which timethe starting material was completely consumed. The hot solution waspoured into rapidly stirred water (200 mL). The resulting mixture wasextracted with chloroform (2×). The combined organic layers were washedwith saturated aqueous sodium bicarbonate and brine, dried overanhydrous sodium sulfate, filtered and then concentrated under reducedpressure to afford a light yellow oil. The material was purified bychromatography over silica gel (95/5 dichloromethane/methanol) toprovide2-butyl-1-[3-(phenylthio)propyl]-1H-imidazo[4,5-c]quinolin-4-amine (1.38g, 3.53 mmol) as a white solid.

Part B

Using the general method of Example 5 Part A,2-butyl-1-[3phenylthiopropyl]-1H-imidazo[4,5-c]quinolin-4-amine (1.38 g,3.53 mmol) was oxidized to2-butyl-1-[3-(phenylsulfonyl)propyl]-1H-imidazo[4,5-c]quinolin-4-amine.The resulting solid was recrystallized from ethanol to provide the titlecompound (0.85 g, 2.01 mmol) as an off-white powder, m.p. 224–227° C.

Analysis. Calculated for C₂₃H₂₆N₄O₂S: % C 65.38; % H, 6.20; % N, 13.26.Found: % C 65.25; % H, 6.23; % N, 13.20.

¹H-NMR (300 MHz, DMSO) δ 7.96 (d, J=8.3 Hz, I H), δ 7.89 (m, 2H), δ 7.73(m, 1), δ 7.63 (m, 3H), δ 7.40 (t, J=8.3 Hz, 1H), δ 7.17 (t, J=8.3 Hz,1H), δ 6.46 (bs, 2H), δ 4.60 (t, J=7.8 Hz, 2H), δ 3.66 (t, J=7.3 Hz,2H), 3 2.86 (t, J=7.8 Hz, 2H), δ 2.04 (m, 2H), δ 1.73 (p, J=7.6 Hz, 2H),δ 1.39 (sextet, J=7.3 Hz, 2H), δ 0.92 (t, J=7.3 Hz, 3H)

MS (CI) for C₂₃H₂₆N₄O₂S m/z 423 (MH⁺), 322, 281

Cytokine Induction Human Cells

An in vitro human blood cell system is used to assess cytokineinduction. Activity is based on the measurement of interferon and tumornecrosis factor (α) (IFN and TNF, respectively) secreted into culturemedia as described by Testerman et. al. In “Cytokine Induction by theImmunomodulators Imiquimod and S-27609”, Journal of Leukocyte Biology,58, 365–372 (September, 1995).

Blood Cell Preparation for Culture

Whole blood from healthy human donors is collected by venipuncture intoEDTA vacutainer tubes. Peripheral blood mononuclear cells (PBMCs) areseparated from whole blood by density gradient centrifugation usingHistopaque®-1077. The PBMCs are washed twice with Hank s Balanced SaltsSolution and then are suspended at 3–4×10⁶ cells/mL in RPMI complete.The PBMC suspension is added to 48 well flat bottom sterile tissueculture plates (Costar, Cambridge, Mass. or Becton Dickinson Labware,Lincoln Park, N.J.) containing an equal volume of RPMI complete mediacontaining test compound.

Compound Preparation

The compounds are solubilized in dimethyl sulfoxide (DMSO). The DMSOconcentration should not exceed a final concentration of 1% for additionto the culture wells. The compounds are generally tested initially atconcentrations ranging from 0.12 to 30 μM. Compounds showing activity at0.12 μM may then be tested at lower concentrations.

Incubation

The solution of test compound is added at 60 μM to the first wellcontaining RPMI complete and serial 3 fold dilutions are made in thewells. The PBMC suspension is then added to the wells in an equalvolume, bringing the test compound concentrations to the desired range(0.12 to 30 μM). The final concentration of PBMC suspension is 1.5–2×10⁶cells/mL. The plates are covered with sterile plastic lids, mixed gentlyand then incubated for 18 to 24 hours at 37° C. in a 5% carbon dioxideatmosphere.

Separation

Following incubation the plates are centrifuged for 5–10 minutes at 1000rpm (˜200×g) at 4° C. The cell-free culture supernatant is removed witha sterile polypropylene pipet and transferred to sterile polypropylenetubes. Samples are maintained at −30 to −70° C. until analysis. Thesamples are analyzed for interferon (α) and for tumor necrosis factor(α) by ELISA

Interferon (α) and Tumor Necrosis Factor (α) Analysis by ELISA

Interferon (α) concentration is determined by ELISA using a HumanMulti-Species kit from PBL Biomedical Laboratories, New Brunswick, N.J.Results are expressed in pg/mL.

Tumor necrosis factor (α) (TNF) concentration is determined using ELISAkits available from Genzyme, Cambridge, Mass.; R&D Systems, Minneapolis,Minn.; or Pharmingen, San Diego, Calif. Results are expressed in pg/mL.

The table below lists the lowest concentration found to induceinterferon and the lowest concentration found to induce tumor necrosisfactor for each compound. A “*” indicates that no induction was seen atany of the tested concentrations (0.12, 0.37, 1.11, 3.33, 10 and 30 μM).

Cytokine Induction in Human Cells Example Lowest Effective Concentration(μM) Number Interferon Tumor Necrosis Factor 1 0.12 0.12 2 0.12 0.37 30.04 0.12 4 0.01 0.01 5 0.01 0.04 6 3.33 10 7 3.33 10 8 10 * 9 3.33 3.3310 1.11 1.11 11 0.01 0.12 12 0.12 10 13 0.12 3.33 14 3.33 10 15 0.04 *16 0.01 0.04 17 0.01 0.04 18 0.01 0.12 19 0.04 0.37 20 0.04 0.37

1. A method of inducing cytokine biosynthesis in an animal comprisingadministering the compound2-butyl-1-[5-(methylsulfonyl)pentyl]-1H-imidazo[4,5-c]quinolin-4-amineor a pharmaceutically acceptable salt thereof to the animal in an amounteffective for cytokine induction wherein the cytokine is IFN-α and/orTNF-α.